Optical, Aesthetic and Ergonomic properties of Night Vision Monoculars - August Questions. - Page 1

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[ARCHIVED THREAD] - Optical, Aesthetic and Ergonomic properties of Night Vision Monoculars - August Questions.

Posted: 8/23/2014 1:58:16 AM EDT

Hi All,

The second in my series of questions about NODs and how you like to use them - as with the last, I've prefaced the questions with some information regarding performance aspects of NODs, so that the decisions that go into making NODs that affect performance can be better understood -

NODs
have come a long way, with respect to goggles and monoculars –
generally the older ones were made from cast metal, have large,
poorly made lenses and had many functional problems. Modern NODS have
exceptional optics, lightweight plastic bodies, exceptional
operational times and cope with most lighting situations.

But
few people consider how the NOD is made, and what it is comprised of,
when considering their selection. Although the PVS-14 has proven
itself one of the most well-developed NODs ever, there are many
variants and performance can vary from variant to variant.

Also,
different applications demand different designs. Water resistant or
waterproof? Lightweight or heavy-duty? Single or dual-tube? Or for
those who tend to the newer, Quad tube? Push button or knob? CR123 or
AA? Extended or narrow diopter adjustments? Fast or slow focus? Long
or short FOV? Russian or American or European design?

These
are common questions and even different models within the same part
can vary – Some early ANVIS goggles came with fine objective and
ocular focus, for pilots who felt the coarse levels of focus in early
models wasn't sufficient. Likewise the ENVIS focus takes quite a few
turns, while the PVS-14 can usually be focused in half a turn.

It
can be difficult to even understand the significance of the
difference without knowing the history, yet buying an expensive NOD
is something that most rush into as a matter of faith. Understanding
the important aspects can make the selection process a lot easier.

In
this article, I'll discuss how different form factors and selections
for housings can make a huge difference to the part use.

Plastic
Lenses vs Glass Lenses.

Most
people pursue glass lenses, but plastic lenses are considerably
lighter – the downside of plastic is that it scratches easily, and
the optical density isn't the same as glass, leading to high
chromatic aberration, yet plastic lenses can reduce lens weight
considerably. Many ocular lenses for the ANVIS style monoculars use a
combination of plastic and glass lenses, likely to make weight
savings.

Folded
optics.

Torque
increases with distance, and so keeping the NOD as close to your face
as possible is important. Folded optics and designs using them allow
for the NOD to sit almost beneath the lip of the helmet. NODs such as
the LUCIE achieve this, acting very much like a flat PVS-7 – while
others such as the PVS-14 are simpler, yet hold a lot of heavy glass
out front.

Size/Weight/Power
and Scale.

Three
important aspects of any NOD – SWaP – follow the progress of all
NV equipment – newer systems such as the Tarsius use 16mm tubes,
while larger 18mm tubes are the most common conventional systems.
Smaller tubes mean smaller lenses, which mean lighter weight – 2mm
isn't much, but if it leads to proportional decreases across all
aspects of a NOD, that means a 30% reduction in weight! However it
also means trading off technological increases in resolution.

Manufacture
Materials.

Metal
is fairly heavy, while engineering plastics are much lighter than
even aluminum, though it's possible to compromise strength for weight
in any material – this is another SWaP category, but it's reflected
in many modern designs which try to remove all extra material and
hollow the design out as far as possible. As most NODs are only
supporting themselves, this isn't a problem unless the NOD is crushed
or receives substantial physical shock.

Balance.

Although balance is often forgotten
outside of ground use of aviation goggles, it's still important. Even
the weight of a PVS-14 will exacerbate the forward tilt of an
ill-fitting helmet and result in positional issues for a NOD user. A
good nape strap and chin strap will alleviate much of that, but can't
eliminate it. On the other hand, counterweights provide protrusions
that can make it difficult to sit in chairs due to pushing the head
forward.

Ocular Aperture

The size of the ocular aperture is
particularly important, as is the extent to which the entire field is
focussed when only viewing it from the edge. A smaller ocular
aperture will bound around too much to see through while running, and
won't allow a full field-of-view when eye relief is extended to
include glasses or other correction, or even with goggles. Also, a
poor lens system will leave the image blurred or distorted when the
eye pupil approaches the edge of the lens, resulting in loss of image
acuity and causing distortion.

In many modern NV systems, the ocular
lens system function is easily forgotten, but it can make a huge
difference to the effectiveness of use of a particular NOD system.

Objective lens performance

Mostly all we hear are T numbers
and F numbers, but these have a major impact on performance. The
objective lens size is constrained by the field of view and the
requirement to bring in more light. Field of view is then affected by
the ocular lens focal distance, such that the monocular is often
designed from the back forward.

Because the objective lens is therefore
matched to the ocular lens for reasons of achieving unity
magnification, it's really important to ensure then that the selected
lens as a high F-number.

F number is a metric that comes from
photography and was originally intended to help in setting film
speeds. In modern night vision use, it can be considered as how much
light it lets through. A F-number of around 1 means the focal length
is the same as the clear lens aperture – so in a 25mm lens system
monocular, that means the lens is also 25mm in diameter. This is
known as a F 1:1 lens – the ratio of focal length to aperture is
1:1. In practice, the second "1” is omitted, and we just call
this a F1 lens.

If the lens is 70% of the diameter -
e.g., 18mm, then it's F1.4 – that is, the ratio of focal length to
aperture ratio is 1.4:1 – this means the lens is about half as
bright.

Most NV lenses need to be F1.4 or
faster (F1 is faster – smaller is better) – otherwise they loose
too much light and the tube will not perform under very dark
conditions as light losses through the system are too great. Losses
due to lenses within a night vision monocular are usually around 90%
for a something like a PVS-14 and can be even higher for cheaper
monoculars. This includes losses through the objective and the
ocular lenses.

As a result, fast lenses of F1.4 to
F1.0 are necessary to minimize losses ( other losses include
reflection and aperture related loss – so this isn't the only loss
) - A good monocular objective lens is around F1.2 and some
exceptional lenses around F1.05 – There are lenses beyond 1 –
such as F0.95, but these are rare and expensive and tend to be heavy.
Also, the higher the F-number, the narrower the depth of field, so
faster lenses will not bring as much into focus.

Now, just to muddy the waters since
I've explained that, other losses are present in a monocular
objective lens. To make allowance for this, they have T numbers –
or TRANSMISSION numbers. T numbers take other losses into account and
provide an estimate for how much light actually gets through a lens
to the image tube. T numbers are always slower ( larger ) than F
numbers, but can vary greatly.

In a PVS-14, the T number and F number
are very close. In a MUM-14, they are further apart, as the MUM-14
objective lens suffers from aperture restrictions within the lens. So
does the SENVG.

In this respect, while the numbers are
close, it's a trade off. Higher T number means more light, which
improves performance. It also means shallow depth of field, which
increases the requirement to refocus the lens system, especially when
looking at objects that are closer.

Additional to all this is the amount of
distortion that the lens itself causes. Issues such as aberration can
cause visual stress and make it difficult to fully use the entire FOV
of the monocular.

Tube surface diameter.

Tube surface diameter is an important
metric. As it gets smaller, the tube gets lighter, the monocular
shrinks and the depth of field increases for a given fixed Field of
View. But the downside is that resolution drops at the same time. For
any given field of view, this equates to a balance between angular
resolution on one hand, and a wide range of performance metrics that
improve at the cost of angular resolution on the other.

This is why the PVS-14 performs so
well, resolution-wise, with such a low tube resolution ( 32 to 45
lp/mm typical ). Yet, it's big, heavy and has a very narrow DoF.

Weight and Mounting

A lightweight NOD is a pleasure to use
– because after you've hung two monoculars and batteries from your
noggin, it can get tiring after a while. Even if you have a strong
neck, the straps holding our NODs to our head aren't perfect, and
ill-fitting equipment is a pain. Counterweights can help, but can
have other issues. ( See Balance ). However even with that taken into
consideration, not all monoculars or mounts are made equally –
Choice of Helmet, Mount and NOD should be made together after,
preferably, having had time to check them all out. No so easy if
you're issue the parts though, or you're still working with the
skullcrusher. Under such circumstances, weight can be a real pain in
the neck.

Yet while light is preferred, as it's
mentioned already, using lightweight parts isn't always possible or
optimal in a NOD/MOUNT/HELMET setup.

Mount Solidity

Ever tried running with your NOD
attached? How was it? Many mounts aren't all that solid, and the USGI
Bayonet fitting is one of the bigger problems. Dovetails are slightly
better, but issues elsewhere can cause the NODs to move up and down
and around, causing the image to be unviewable, especially if you
have a narrow aperture ocular lens.

Solutions often include
screw-adjustments to remove slack, bungees to hold things tight by
removing lash and even use of tape to take up space within the
mounting mechanism.

Control Access

Are you a gymnast? No. I bet you've
felt like one sometimes having to turn on a NOD with the opposite
hand – Control access is important, as is function. The
three-position knob is standard, but I've seen people struggle with
IR discipline modifications many times, sometimes even dislodging the
removing the NOD accidentally while trying to pull/push/twist
whatever strange combination is required. Some use push-button
timing, which can be easy, so long as you don't accidentally go IR
active under the wrong circumstances, and under some circumstances,
taking a few seconds to go IR active could be detrimental to what
you're doing, especially as you enter a building. Turning off a
push-button light in a hurry can be difficult too, and often results
in turning the entire NOD off.

Power Source / Consumption

Most of us are pretty happy with our
NODs, but we still have to carry batteries. 40 hours is a lot, unless
you're using your NOD every night for months on-end. It's not
uncommon under warfare situations to run out of batteries and have
difficulties with supply, especially if a range of batteries are
required. Likewise preppers may also forget the NOD batteries, but no
one wants to carry buckets of batteries with them when mobile either?

Bigger batteries also allow more
operation from a single battery use, but don't last as long. CR123
seem preferred, but are harder to get. AA are easy, but two AA's are
heavy, and single AA's last half as long. Better performance of tubes
helps a lot – We've seen typical AA times from double batteries for
20 hours move out to single batteries for 50 hours. But on
multi-tube systems, it gets more complicated. A single AA won't cut
it, and battery packs as counterweights are often worn.

Yet some people are happy with a few
hours of operation, and battery packs don't bother them. This is
often the case with digital users, who can easily replace batteries
several times in one night.

Another issue is rechargables, which
some prefer, but which many manufacturers warn against, due to the
voltages put out by NiMH and NiCD batteries. Likewise, some AA format
batteries can put out over 4v as a rechargable, but are marked as
AA's.

The issue here isn't obvious, but it's
there, hidden in the detail behind what the power is used for - Most
tubes are very low power users, but modern CPUs allow greatly
enhanced options for use – especially where high-speed timing is
involved.

But the overall power consumption must
be matched to application, so understanding what power consumption
requirements you have is still important in NOD selection and design.

Tube Performance Specific
Characteristics

Photocathode spectral response

Even the tube itself can affect the
quality of the image, far outside of concerns such as gain and
operational characteristics. Phosphor selection and Photocathode
selection. Moonlight is primarily the same, spectrally speaking, as
sunlight, but appears different to us due to the PurjinkeShift.
Starlight provides a lot of near-infrared light and skyglow gives off
energy at a variety of different wavelengths.

Likewise, not everything is the same
color. Different albedo responses for different environments will
reflect different amounts of radiation, and once it's through the
image intensifier, we're monochromatic in terms of vision. However
this is all affected by the spectral sensitivity of the photocathode.

If the scene being observed is
primarily the same color as the peak response of the tube, this will
provide a bright image, but detail will be lost as contrast is no
longer present between different physical items and everything in
sight because camouflaged, with only brightness available to
differentiate things.

This is why, under extremely dark
environments, vegetation is quite bright but it all seems to blend
into itself as most vegetation reflects very strongly in the
near-infrared region under NV use, but is very dark under the visual
gamut.

As a result, as these conditions
usually occur in overcast conditions, the sky and ground can blend
into each other, with each illuminated with a similar amount of IR
light. Under these conditions, it's not the gain of the image
intensifier that's important – it's the different in the amount of
light being reflected from the ground and from the sky. In simple
terms, it's more about environment contrast than it is about
signal-to-noise.

Phosphor

Different phosphors work differently in
NV devices, and can enhance vision under some situations and detract
from performance in others. Most phosphors are P43 and P22, which are
both green, but many white phosphors are now coming onto the market.

Some people feel green offers the best
resolution and performance for both scotopic and mesopic vision,
while it makes it somewhat difficult under photopic conditions. White
phosphors offer something more akin to black and white images from
old TV sets – familiar to an older generation but unlikely to have
been encountered by the majority of modern NV users.

But phosphors are more than just a
color preference. The efficiency and time to decay ( how long they
glow for after an electron strike ) are important factors. If the
decay time is too long, then streaks will occur in brighter
conditions, and this will induce blurring also with motion. On the
other hand, too-short a response not only frequently results in a
duller image, but under very dark conditions, the image can break up
and higher resolutions are quickly lost to the eye, along with edge
detail and, in extreme circumstances, the entire image looks more
like a snowstorm than a picture as our brain loses the ability to
integrate multiple frames into a meaningful image.

Additionally, phosphor thickness
affects resolution and brightness in opposite ways ( more resolution
= less brightness ) and a bad phosphor choice can be difficult to
look at.

Noise

Somewhat affected by the photocathode
and phosphor, noise isn't as easy to categorize as the other two –
it can be generated in the photocathode side of the tube ( Electron
spread, dark voltage, ion-strikes, halo etc. ) or in the phosphor (
streaking, decay time, halo if severe, blooming ) but it can also
come from the MCP, which generates quite a bit of noise at higher
gain levels.

Overall, noise breaks down the image
quality, and some noise rarely contributes to S/N ratio measurements.
Ion strikes, for example, are the small bright dots you see all over
a dark image when using a NOD. This scintillation can be very
off-putting and if severe can even mask important low-light events,
causing significant frustration for a user – especially in
situations such as search and rescue.

Noise such as this is most common on
high S/N Filmless tubes, when the image is exceptional and the
dark-levels sufficient to see negative-space images quite well, yet I
know people who cannot stand filmless tubes for exactly that reason.
Under such conditions, image noise is enough to move them to
thin-filmed, which provide a much more even image in most
circumstances, yet sometimes lose the negative-space images that can
be important for tactical situations.

Also, noise doesn't have to be dynamic
to cause issues for NOD users. Fixed pattern noise, blemishes and
dark spots can also cause similar issues, despite being relatively
fixed in the field of vision, mainly because out eyes are constantly
scanning the image -

Picking a suitable tube for a
comfortable NOD is relatively important. It's the heart and function
of many systems and it's one of the most noticed aspects of system
performance.

So what is preferred?

Not all of the important properties of
NODs are optical. Many are Aesthetic and Ergonomic, but in the case
of a well-made NOD, all these properties blur into one that affects
how useful they are to us, especially under extended use.

OK, now the questions related to NODs
now – as per last month, this information is being collected and
returned to a manufacturer to provide insight into what the market is
looking for, and to direct development of new technologies.

Q1.
Image Quality/comfort point-of-view: is the Intensified image tiring?
Why (noise, brightness, …)? (Noisiness of the image means more
"turbulent”/less stable image ) -

Q2.
What is the performance improvement that would be a compelling reason
to upgrade or change your NVG?

Q3.
What is the added feature that would be a compelling reason to
upgrade or change your NVG?

Q4.
What is the change in image quality/"comfort” of image that would
be a compelling reason to upgrade or change your NVG?

As
a guide, consider what the biggest issues are that you are currently
experiencing. Do you find NV goggles tiring to use? Do you struggle
seeing objects deep in shadows on dark nights? Do you find the range
of your goggles just isn't enough, especially without adding more
light? Are they too heavy? Do they use batteries too quickly? Are
they too heavy? Do they fit correctly? Do they wobble when you run?
These individual questions are rhetorical, but should assist in
answering the four above questions.

And,
if you've thought the above through and know what you want, without
limitations, a bonus question -

Q5.
What are the other improvements expected from Night Vision Goggles?

Well,
I look forward to hearing what the forum has to say. I've tried to
cover all the bases from a simple perspective, but feel free to add
other details also if you feel I've left some of the important
details out -

And
again, while I'm encouraging public participation, you can also send
me PMs or Emails with responses if you prefer -

Thanks

David.

Posted: 8/23/2014 10:07:21 AM EDT

[#1]

I know this may not be what you're looking for, but ideally I'd like, as you mentioned above, a MUCH "flatter" set of binocular-style NODs with a much greater FoV. 40* just isn't cutting it, and dual tubes stick out 8-inches from your eyes. Something like a PVS-21 would be nice, but the weight is too much, not to mention the cost of entry.

Posted: 8/23/2014 10:29:27 AM EDT

[#2]

like what horta said im not sure if this is what you are looking for and im still a rookie in the NVG game.

The single thing that would have me saying "hey im going to sell my pvs14 to fund this" would be something with a higher field of vision. when im out at night and hear something or trying to catch up with a coyote I find myself trying to "point" (for lack of better words) my nods in the direction I feel i need to see.

the lack of peripheral vision is the one improvement that would have me looking to upgrade. I keep my nods off my face a little and sometimes I catch myself looking out of the night vision to see my peripheral.

the GP18's is a step in the right direction for this, but I know only a handful of people who could afford them.

ETA: do night vision "tubes" require that they be built in a circular housing? Why not a rectangle?

Posted: 8/23/2014 10:46:06 AM EDT

[#3]

Hi guys,

To be honest, I interpret the questions myself also, so I decided not to provide any guidance to answering them - I think the answers can be really open as well - From what you find difficult to use with existing nods ( eg, tiring, not bright enough, no color, poor contrast, depth perception issues etc ) to what you'd like to see ( Wide FOV, non-unity aspect ratio, superlightweight, multitube, non-circular lenses, virtual imaging - pretty much anything at all... ) -

I'll answer the questions myself too - since I didn't write them I like to think I have a valid perspective also - .... And I really love the idea of rectangular NODS as mentioned... Something wide-view with a single lens... After all, lenses don't have to be round do they?

David.

Posted: 8/23/2014 7:48:03 PM EDT

[#4]

I have been lurking in this section for some time and now that I have picked my own set of NVGs I will be posting a bit here and there. I have used NODs on and off over the years, mostly PVS-7s and PVS-14s. I now own a set of PVS-15s.

In order of importance for me follows

For me with the level of tubes today I feel that the biggest areas of improvement I'd like to see would be in ergonomics and flexiblity. I never really played nice with the -14s, it almost always felt as if I was fighting the controls of the -14s. For mono unit I would like to see a body style more along the lines of the PVS-18 with the mount, controls and power supply right under the mount arm and just the tube in fornt of my eye

I would also like to see the power supply flexiblity along the lines of the PVS-31s and Sentinels with being able to use helmet mounted battery packs. I think keeping the on board power supply is a must for a few reasons, one - for those of use who are not issued gear it's one less thing to buy. And two - if the battery pack fails or the cable breaks the unit can still work.

As for manual gain, for me its a mixed bag. It is nice to have but I've found myself forgetting about at times and at other times spending too much time messing with it. Manual gain on or off a unit is not a deal breaker for me.

As for folded optics. Having heard from those who have used PVS-21s they seem to have a real small role that they can fill very well. I have heard that most feel better served by standard units. One man said he would much rather use PVS-14s over -21s. YMMV. But shorter units would be nice as along as performance is not lost.

EDIT- I would like to at least see a PVS-14 with the battery at the rear of the unit instead of the front. Where it is now on the single battery unit it gets in my way for both the focus and gain, more so when using a dual dovetail mount

Posted: 8/24/2014 5:53:34 PM EDT

[#5]

Q1. Image Quality/comfort point-of-view: is the Intensified image tiring? Why (noise, brightness, …)? (Noisiness of the image means more "turbulent”/less stable image )
- I rarely use NODs for prolonged times when it could become tiring, but under moonlight conditions with a monocular bad optical path offset (collimation?) is tiring.

Q2. What is the performance improvement that would be a compelling reason to upgrade or change your NVG?
- Field of view of 60 or more
- More resolution when in very low light environments (under heavy tree cover starlit night).
- Don't know how it could be done, but more contrast to foliage. With binoculars it's a lot easier to see in dark with heavy foliage as stereo vision helps to differentiate which bush is which, but with a monocular it all looks like a big flat green blob
- More "dynamic range" to see into the shadows in moderately lit environments. I have dreamed of a tube that would adjust the voltage of each MCP "cell" individually depending on the amount of electrons hitting it. No idea if that would do any good, but sounds good to my ear

Q3. What is the added feature that would be a compelling reason to upgrade or change your NVG?
- My recent problems with a MUM collimation might affect my opinion here, but every monocular should have a method to adjust the collimation. If it was an upgrade eyepiece I would probably purchase it
- Another added feature that could be purchased separately would be a external battery pack that can be connected to the standard AA or CR123 slot

Q4. What is the change in image quality/"comfort” of image that would be a compelling reason to upgrade or change your NVG?
No answer

Posted: 8/26/2014 2:22:00 AM EDT

[#6]

Q1. Image Quality/comfort point-of-view: is the Intensified image tiring? Why (noise, brightness, …)? (Noisiness of the image means more "turbulent”/less stable image )

I personally find that intensified images are not tiring at all. I've used a variety of different NVG tubes in a number of different conditions and I never have experienced eye strain. I will note that an Amber Filter does make the image much softer on the eyes,

I will say that noise, while not being uncomfortable, can have negative effects. I had an incredibly noisy Photonis Tube, probably 15 years old. The gain on it was unreal. The brightness of the image, as well as what was visible, rivaled Gen 3. Even down to unforgiving light conditions you could still navigate and see where trees were and get a general idea of how you are navigating.

The issue with that tube was in it's noise level. It was bad when it got dark. Even though you could still clearly define a man standing in a field from a bush, and a bush from a tree, you lost any appreciable detail beyond that. At one point I had difficulty determining if I was walking on the dirt path, or the grass. I could see it was ground. I could see where the tents were, where we parked our car. I could see there was a tree directly in front of me. I just could not determine if I was standing on the grass or the dirt. This issue arose many other times that night. I imagine I would have difficulty IDing a dog as opposed to a wolf, coyote, or other four legged animal of a similar size.

When we compared it with a Gen 3 device, the Gen 3 device had the exact same level of gain. It produced almost the same image, instead it looked like someone had went in and filled in the detail. Even though the other tube was noticeably noisy, it wasn't tiring. It didn't strain or stress my eyes. If I were to be stuck with it and not have a better alternative? I'd manage.

Q2. What is the performance improvement that would be a compelling reason to upgrade or change your NVG?

We seem to be topping out on performance with Gen 3. Gen 3 performance has steadily rose over the past ten years but for the most part it's now usable in almost every condition. Filmless tubes can apparently produce an image in no moon, heavy overcast under a thick forest canopy. There isn't really much further you can go with the technology, nor is there a reason to. It can now preform flawlessly in 99% of conditions.

When the rest of the world catches up in the next 5-10 years, we will have all we need from NVG's. We already have Autogated Gen 3 tubes being pumped out of a couple of countries, we have Photonis's top of the line Gen 2 still somehow getting better. There isn't much to go on performance of an intensifier tube until someone in the world has Unfilmed, Gen 3 tubes to sell to the rest of us. Even if we never get it, what we have access to on the international market right now is incredibly competitive.

Q3. What is the added feature that would be a compelling reason to upgrade or change your NVG?

Thermal Integration. The price of thermal is coming down to the point of absolute stupidity. The fact that the Therm App is a thousand dollars means that a clip on thermal system for monoculars should be within the realm of 2-3 thousand dollars. Now having a clip on system isn't exactly an upgrade, but it would be a step in the right direction.

If a company were to sell a moderately priced thermal housing that could accept PVS-14 optics and tubes (with gain) - this might create an irresistible upgrade for many. Basically a build your own fusion AN/PSQ-20 DSNVG. Send in your PVS-14, get it installed in the unit with your eye piece and objective lens? People would click that link in a heart beat to check out the price. If you could somehow manage to do it for around 4,000? You'd have people lined up around the block.

I imagine the only reason the pricing on this sort of technology has not come down, even though the component costs have, is to try and milk the teet that is .mil contracts. There is a lot of milk to be had.

The more realistic suggestion? Weight. Weight is huge. If one could produce a monocular that clocks in at half the weight of a PVS-14? It would sell like hot cakes... Well someone did make it, it's just not available on the consumer market.

http://elbitsystems.com/Elbitmain/files/Xact_NV32.pdf

If I could get that? 100% immediate, automatic upgrade. It weights less than half of a PVS-14, accepts a bridge system, and is absolutely tiny. If I could get my hands on that? Absolutely. The ability to wear two of these things and have it come out as weighting the same as a typical monocular is key.

I would answer questions 4-5 but it seems I may have inadvertently answered those questions in my previous answers. Even though I went off topic a tad I hope some of this could be of help.

Posted: 8/26/2014 7:26:53 PM EDT

[#7]

I'm a little blown away by the no no on using rechargeable batteries. I've been using Enloop rechargeables in my single battery PVS14's since I got them with no ill effects but I understand why they aren't the best to use now and I'm rethinking my use. Lithium non rechargeables were listed as first choice so what's everyone using? Energizer? I found this link showing the Energizer advanced lithium puts out 1.8v initially, so according to the reasoning these also are a no go. Correct?

link

Posted: 8/27/2014 5:37:52 PM EDT

[#8]

Quote History

Quoted:

I'm a little blown away by the no no on using rechargeable batteries. I've been using Enloop rechargeables in my single battery PVS14's since I got them with no ill effects but I understand why they aren't the best to use now and I'm rethinking my use. Lithium non rechargeables were listed as first choice so what's everyone using? Energizer? I found this link showing the Energizer advanced lithium puts out 1.8v initially, so according to the reasoning these also are a no go. Correct?

link

View Quote

Ahh, that's a good point - I never really thought about power worries as a major concern for NODs.. What can be used, what voltage ranges are acceptable - I guess the logic goes that the military always use the correct battery but in a conflict, I guess there's a desire that any battery will do.

Energiser Lithiums should be fine in your NOD. I don't think there's really any problems with using other batteries such as Enloops - but be careful to avoid LiPo AA batteries - they have around 4v on them when charged... But are a normal AA size. One of my own designs used these, and got good results, but it had a voltage input range from 2.5v to about 16v so could take anything you could connect it to - But that was more to make effective use of Lithium Polymer - which are not good in conventional NV, but the voltage draw on this was pretty high because the tube was a 12v system, so I used voltage converters.

Anyway, I think the Lithium thread from a long time ago ( 1.5v Lithiums, no LiPo Lithiums ) determined that the reasons for choosing Energiser Lithium were related to other factors, not whether or not the voltage was as desired - mainly around leakage, temperature range and longevity...

David

Posted: 8/27/2014 5:54:29 PM EDT

[#9]

Well, I did say I'd give my own answers :)

Q1. Image Quality/comfort point-of-view: is the Intensified image tiring? Why (noise, brightness, …)? (Noisiness of the image means more "turbulent”/less stable image ) -

For me, turbulent images make it really difficult to see what's going on - If the image gets very dark and I start to see it as a series of "photon strikes" - rather than a continuous image, I have a lot of trouble putting that information together in my head, but it only happens under extreme dark. NL6...

The thing I find most tiring about NV is when it's too bright - I find using thermal a real problem because of this. And I often find myself turning down the gain to get a clearer image while operating - always searching for the closest I can get to "green glass" -

Q2. What is the performance improvement that would be a compelling reason to upgrade or change your NVG?

Not a great questions for me... The compelling reason to upgrade or change my NVG would be because there's another one on offer... I didn't collect what I have by accident.

But if it was based on economics, I'd say a significant image would be it - For example, when I had Gen1, Gen2 was a huge step... Then smaller lighter Gen2... Then I got Gen3 and it was difficult to go back to Gen2... Finally I got good Gen3, and even older Gen3 are hard to go back to. Also, over time, I get a favourite... My favourite is definitely the PVS-14 but second is the MUM-14.

I guess it's easiest to answer this question in retrospect... When I've seen a better technology, it's hard to go back to what I had or saw before... This for me is the "reason"... If it would be hard to go back, it's time to upgrade to what made me feel that way. That's a pretty compelling reason... Of course, options aren't always easy, and I still mourn the loss of my XR5 system :(

Q3. What is the added feature that would be a compelling reason to upgrade or change your NVG?

Added feature? See question 2.. Anything that made me not want to go back to what I have after learning of the feature... Personally, I'd like integrated data display capability in a tube :) I wonder if that's possible. I'd like fusion too... And augmented reality... I'd love a '21 but it's not on the list of what I can get hold of... I like quad's too, but that's more attainable for me, still I guess a wide screen NOD would be ideal, with two tubes and high overlap.

And lightweight... I really hate weight that's unbalancing.

Q4. What is the change in image quality/"comfort” of image that would be a compelling reason to upgrade or change your NVG?

Weight.... Weight....., Weight.... OK and better ocular standoff... Eye Relief is important because I wear glasses.

Q5. What are the other improvements expected from Night Vision Goggles?

Augmented reality - but hey, I'd settle for a built in laser rangefinder ( though I don't really have to.... )

Yep, range data, image data, stuff like that - This is what I want to see.

And lightweight... And really lightweight... And to stop banging it on the roof of low-clearance vehicles.

Regards

David

Posted: 8/27/2014 7:44:08 PM EDT

[#10]

Quote History

Quoted:

Ahh, that's a good point - I never really thought about power worries as a major concern for NODs.. What can be used, what voltage ranges are acceptable - I guess the logic goes that the military always use the correct battery but in a conflict, I guess there's a desire that any battery will do.

Energiser Lithiums should be fine in your NOD. I don't think there's really any problems with using other batteries such as Enloops - but be careful to avoid LiPo AA batteries - they have around 4v on them when charged... But are a normal AA size. One of my own designs used these, and got good results, but it had a voltage input range from 2.5v to about 16v so could take anything you could connect it to - But that was more to make effective use of Lithium Polymer - which are not good in conventional NV, but the voltage draw on this was pretty high because the tube was a 12v system, so I used voltage converters.

Anyway, I think the Lithium thread from a long time ago ( 1.5v Lithiums, no LiPo Lithiums ) determined that the reasons for choosing Energiser Lithium were related to other factors, not whether or not the voltage was as desired - mainly around leakage, temperature range and longevity...

David

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Quoted:

Quoted:
I'm a little blown away by the no no on using rechargeable batteries. I've been using Enloop rechargeables in my single battery PVS14's since I got them with no ill effects but I understand why they aren't the best to use now and I'm rethinking my use. Lithium non rechargeables were listed as first choice so what's everyone using? Energizer? I found this link showing the Energizer advanced lithium puts out 1.8v initially, so according to the reasoning these also are a no go. Correct?

link

Ahh, that's a good point - I never really thought about power worries as a major concern for NODs.. What can be used, what voltage ranges are acceptable - I guess the logic goes that the military always use the correct battery but in a conflict, I guess there's a desire that any battery will do.

Energiser Lithiums should be fine in your NOD. I don't think there's really any problems with using other batteries such as Enloops - but be careful to avoid LiPo AA batteries - they have around 4v on them when charged... But are a normal AA size. One of my own designs used these, and got good results, but it had a voltage input range from 2.5v to about 16v so could take anything you could connect it to - But that was more to make effective use of Lithium Polymer - which are not good in conventional NV, but the voltage draw on this was pretty high because the tube was a 12v system, so I used voltage converters.

Anyway, I think the Lithium thread from a long time ago ( 1.5v Lithiums, no LiPo Lithiums ) determined that the reasons for choosing Energiser Lithium were related to other factors, not whether or not the voltage was as desired - mainly around leakage, temperature range and longevity...

David

Do you have a link to that thread? I'd be interested in taking a look, because now I'm a little confused. Is anything over 1.5v truly that bad and what batteries should a owner who wants the best be? I'm sure a MUM would be fine, and probably not a good idea for dual battery PVS14's, but what about single battery units? I'm thinking if Lithium's are the top choice, then a good number of people are probably using the Energizers which have over 1.5v. Leaking and battery quality aside, how big a deal is output really?

Trivial battery questions aside, and to answer your initial post. I'm in 100% agreement with lighter weight being at the top of that list. What if a complete NV unit was the size of just the tube? Dedicated helmets would be a thing of the past. You could clip them on a set of glasses or goggles and go. How awesome would that be!?! FOV is another I'd like to see improved. Looking through a toilet paper roll that let's you see in the dark is pretty cool, but what if it had twice the FOV? Again I agree with you about seeing progressively better tech changing your opinion. Case and point, the other night me and a friend took two of my PVS14's out for a hike. One is a L3 Omni VIII I just got, and the other was identified by you (David) as a commercial tube around Omni VI or VII performance. I started with the commercial tube, and he with the L3. We switched about halfway and what a difference! These are both my tubes and know what they look like, and it still blows me away when viewed side by side or back to back. Now I just saw another members amazing pics he took through a filmless tube, and of course the cogs start turning!

ETA:
Another thing I thought of not long ago, why isn't there a auto focus available yet? Cameras and even cell phones have auto focus....so why not NV? Could be a possible weight and bulk issue, but surly I'm not the first person to ask why not.

Posted: 8/31/2014 8:16:20 AM EDT

[#11]

Quote History

Quoted:
Do you have a link to that thread? I'd be interested in taking a look, because now I'm a little confused. Is anything over 1.5v truly that bad and what batteries should a owner who wants the best be? I'm sure a MUM would be fine, and probably not a good idea for dual battery PVS14's, but what about single battery units? I'm thinking if Lithium's are the top choice, then a good number of people are probably using the Energizers which have over 1.5v. Leaking and battery quality aside, how big a deal is output really?

Trivial battery questions aside, and to answer your initial post. I'm in 100% agreement with lighter weight being at the top of that list. What if a complete NV unit was the size of just the tube? Dedicated helmets would be a thing of the past. You could clip them on a set of glasses or goggles and go. How awesome would that be!?! FOV is another I'd like to see improved. Looking through a toilet paper roll that let's you see in the dark is pretty cool, but what if it had twice the FOV? Again I agree with you about seeing progressively better tech changing your opinion. Case and point, the other night me and a friend took two of my PVS14's out for a hike. One is a L3 Omni VIII I just got, and the other was identified by you (David) as a commercial tube around Omni VI or VII performance. I started with the commercial tube, and he with the L3. We switched about halfway and what a difference! These are both my tubes and know what they look like, and it still blows me away when viewed side by side or back to back. Now I just saw another members amazing pics he took through a filmless tube, and of course the cogs start turning!

ETA:

Another thing I thought of not long ago, why isn't there a auto focus available yet? Cameras and even cell phones have auto focus....so why not NV? Could be a possible weight and bulk issue, but surly I'm not the first person to ask why not.

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Quoted:

Quoted:

I'm a little blown away by the no no on using rechargeable batteries. I've been using Enloop rechargeables in my single battery PVS14's since I got them with no ill effects but I understand why they aren't the best to use now and I'm rethinking my use. Lithium non rechargeables were listed as first choice so what's everyone using? Energizer? I found this link showing the Energizer advanced lithium puts out 1.8v initially, so according to the reasoning these also are a no go. Correct?

link

Ahh, that's a good point - I never really thought about power worries as a major concern for NODs.. What can be used, what voltage ranges are acceptable - I guess the logic goes that the military always use the correct battery but in a conflict, I guess there's a desire that any battery will do.

Energiser Lithiums should be fine in your NOD. I don't think there's really any problems with using other batteries such as Enloops - but be careful to avoid LiPo AA batteries - they have around 4v on them when charged... But are a normal AA size. One of my own designs used these, and got good results, but it had a voltage input range from 2.5v to about 16v so could take anything you could connect it to - But that was more to make effective use of Lithium Polymer - which are not good in conventional NV, but the voltage draw on this was pretty high because the tube was a 12v system, so I used voltage converters.

Anyway, I think the Lithium thread from a long time ago ( 1.5v Lithiums, no LiPo Lithiums ) determined that the reasons for choosing Energiser Lithium were related to other factors, not whether or not the voltage was as desired - mainly around leakage, temperature range and longevity...

David

Do you have a link to that thread? I'd be interested in taking a look, because now I'm a little confused. Is anything over 1.5v truly that bad and what batteries should a owner who wants the best be? I'm sure a MUM would be fine, and probably not a good idea for dual battery PVS14's, but what about single battery units? I'm thinking if Lithium's are the top choice, then a good number of people are probably using the Energizers which have over 1.5v. Leaking and battery quality aside, how big a deal is output really?

Trivial battery questions aside, and to answer your initial post. I'm in 100% agreement with lighter weight being at the top of that list. What if a complete NV unit was the size of just the tube? Dedicated helmets would be a thing of the past. You could clip them on a set of glasses or goggles and go. How awesome would that be!?! FOV is another I'd like to see improved. Looking through a toilet paper roll that let's you see in the dark is pretty cool, but what if it had twice the FOV? Again I agree with you about seeing progressively better tech changing your opinion. Case and point, the other night me and a friend took two of my PVS14's out for a hike. One is a L3 Omni VIII I just got, and the other was identified by you (David) as a commercial tube around Omni VI or VII performance. I started with the commercial tube, and he with the L3. We switched about halfway and what a difference! These are both my tubes and know what they look like, and it still blows me away when viewed side by side or back to back. Now I just saw another members amazing pics he took through a filmless tube, and of course the cogs start turning!

ETA:

Another thing I thought of not long ago, why isn't there a auto focus available yet? Cameras and even cell phones have auto focus....so why not NV? Could be a possible weight and bulk issue, but surly I'm not the first person to ask why not.

I can't recall the thread title, and it wasn't just one thread but a long series of threads over half a decade, but if you look into the following google search;

https://www.google.com.au/?q=energiser+lithium+night+vision+site:ar15.com#q=energiser+lithium+night+vision+site:ar15.com

You'll find that Energiser Lithiums are considered the defacto "best" AA for NODs...

Auto focus eh? I'm not sure I'd want it in my NOD - more to go wrong, more to break, but I guess there are times that I'd like to be able to auto-focus on something... Though ideally, what I'd really like to see there is a camera watching my retina and adjusting the external lens focus ( and rear focus ) to match my eye, so as I looked around the NOD at different parts of the image, that part came into focus... I guess I'd even settle for just focusing the part of the image I was looking at.

It will become a standard feature at some point I think though - but I have no idea whether it will be successful or not.

But I can't imagine a simple camera-like autofocus being popular - Just think of all those videos you record on your phone and you can't get the focus right... Now imagine looking at a threat that is looking to harm you... And the blurry image transition suddenly becomes a little less desirable.

Aside from FOV, how are people about the whole eye relief bit? And also, edge-focus quality and matters like that?

Fundamentally though, it's still about the picture - and when looking between even an older PVS-14 and a newer PVS-14, you can tell the difference, as you noticed. Both are quite capable, but with one you get more range, better detail and a brighter image. Also, the image itself is important. One of the fundamental differences between Gen2 and Gen3, aside from image quality, is that Gen3 makes vegetation look a lot brighter - sometimes that's good, but sometimes you end up with the entire image at the same brightness level - brighter isn't always good if you really need contrast...

David

Posted: 8/31/2014 8:36:16 AM EDT

[#12]

Quote History

Quoted:

Ahh, that's a good point - I never really thought about power worries as a major concern for NODs.. What can be used, what voltage ranges are acceptable - I guess the logic goes that the military always use the correct battery but in a conflict, I guess there's a desire that any battery will do.

Energiser Lithiums should be fine in your NOD. I don't think there's really any problems with using other batteries such as Enloops - but be careful to avoid LiPo AA batteries - they have around 4v on them when charged... But are a normal AA size. One of my own designs used these, and got good results, but it had a voltage input range from 2.5v to about 16v so could take anything you could connect it to - But that was more to make effective use of Lithium Polymer - which are not good in conventional NV, but the voltage draw on this was pretty high because the tube was a 12v system, so I used voltage converters.

Anyway, I think the Lithium thread from a long time ago ( 1.5v Lithiums, no LiPo Lithiums ) determined that the reasons for choosing Energiser Lithium were related to other factors, not whether or not the voltage was as desired - mainly around leakage, temperature range and longevity...

David

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Quoted:

Quoted:
I'm a little blown away by the no no on using rechargeable batteries. I've been using Enloop rechargeables in my single battery PVS14's since I got them with no ill effects but I understand why they aren't the best to use now and I'm rethinking my use. Lithium non rechargeables were listed as first choice so what's everyone using? Energizer? I found this link showing the Energizer advanced lithium puts out 1.8v initially, so according to the reasoning these also are a no go. Correct?

link

Ahh, that's a good point - I never really thought about power worries as a major concern for NODs.. What can be used, what voltage ranges are acceptable - I guess the logic goes that the military always use the correct battery but in a conflict, I guess there's a desire that any battery will do.

Energiser Lithiums should be fine in your NOD. I don't think there's really any problems with using other batteries such as Enloops - but be careful to avoid LiPo AA batteries - they have around 4v on them when charged... But are a normal AA size. One of my own designs used these, and got good results, but it had a voltage input range from 2.5v to about 16v so could take anything you could connect it to - But that was more to make effective use of Lithium Polymer - which are not good in conventional NV, but the voltage draw on this was pretty high because the tube was a 12v system, so I used voltage converters.

Anyway, I think the Lithium thread from a long time ago ( 1.5v Lithiums, no LiPo Lithiums ) determined that the reasons for choosing Energiser Lithium were related to other factors, not whether or not the voltage was as desired - mainly around leakage, temperature range and longevity...

David

Lithiums are considerably lighter as well.

Posted: 8/31/2014 9:56:10 AM EDT

[#13]

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Quoted:
... focusing the part of the image I was looking at. ... will become a standard feature at some point I think though - but I have no idea whether it will be successful or not.

David

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There has been some success in developing flat (like really flat, a few atoms thick) lenses that capture and retransmit the photons, but retain information like the direction from which it came from. If with similar technology it could be made that the intensifier tube would pop the photons out at the same angle they came in we could have the entire view focusable with your eye as with 1X zoom it would essentially be just like looking without the optics.

Posted: 8/31/2014 8:58:01 PM EDT

[#14]

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Quoted:
There has been some success in developing flat (like really flat, a few atoms thick) lenses that capture and retransmit the photons, but retain information like the direction from which it came from. If with similar technology it could be made that the intensifier tube would pop the photons out at the same angle they came in we could have the entire view focusable with your eye as with 1X zoom it would essentially be just like looking without the optics.

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Quoted:

... focusing the part of the image I was looking at. ... will become a standard feature at some point I think though - but I have no idea whether it will be successful or not.

David

There has been some success in developing flat (like really flat, a few atoms thick) lenses that capture and retransmit the photons, but retain information like the direction from which it came from. If with similar technology it could be made that the intensifier tube would pop the photons out at the same angle they came in we could have the entire view focusable with your eye as with 1X zoom it would essentially be just like looking without the optics.

You know, I forgot to include recent scientific advances in my earlier comments, and I just realized, it really is possible to achieve this....

Holographic displays might well eliminate the need to have ocular lens focus mechanisms, and would allow, theoretically, multiple focal paths through a holographic medium such that your eyes would focus on any part they observed, including looking around. Additional to this, it would be possible to build the display as either a 3D construction of what the NOD saw, or could be a single flat field projected at a distance.

Additionally, it's possible to use the same mechanism that the new infinite-depth-of-field cameras use, with image processing, to allow a single very small lens ( thing very light and very small, like maybe 1/2" across, and 1/4" from the tube ) such that the image is processed digitally and it takes cues from your eyes and adjusts focus automatically.

This approach would solve the issue at both ends - Pilots could look at their instruments then back out to the real world at infinity, and their goggles would adjust focus automatically, not by mechanical mechanism, but using the same image processing technology as cameras do - This would actually make it possible to have an entire NOD the size of a tube, and very lightweight. There would be a necessary digital processing requirement, so what we're talking about is a CCD based image intesifier and digital screen, but there's no reason such a NOD couldn't be under 1" in total length, including lenses, and weigh well under 100 grams....

So yes, based on new technology, it really is possible to build supertubes like that, even with current technology, which can automatically adjust for far-field focus, electronically, based on either an algorythm, cues ( eg, in-cockpit cues such as markers, depth indicators, etc ) or even based on the eyes of the person using the NODs.

Such a technology would take NODs closer to augmented reality, and would be a significant leap in technology - it would be enough of a generational change to make it difficult for opposing forces armed with non-adjusting NODs to compete effectively.

It's actually pretty neat too, because I only just realized the technology already exists... Or to take it a step futher, there is actually another technology called "optical waveguide" that appeared in a far-off booth at CES 2012 and vanished... Add that in, and you have a pair of either normal or prescription eyeglasses, with a NOD integrated into them, which overlay video directly onto the user's vision with intensified images - PVS-21 style, but without the bulk and weight. So, yes, I take back my earlier comments - it is possible to fit a NOD into a pair of glasses, and use optical waveguide for both objective and ocular lenses, to create auto-adjusting focus and possibly even holographic intensified vision. With a super-small tube embedded into the frame... And did I mention that recent processor technology has found a way to avoid the vacuum requirement by using helium at low pressure, so that it doesn't block electrons?

Yep, it seems all the technology really does exist at the moment... Well, I reckon battery life would suck... So it's not perfect.

Hmmm, last time I wrote up about a technology like this, I got contacted by the manufacturer asking me how I got permission to release the information publicly and if they could talk to me about it? LoL!... And I had to tell them it was just fiction... They never spoke to me again :( But these ideas are definitely going into my next scifi book.

I suppose the next question is how far along the line is current technology - Anyone want to take a guess?

David

Posted: 9/1/2014 12:28:35 AM EDT

[#15]

PVS 14 Pinnacle user here.

More gain / less noise would still be an big improvement on dark nights. It may be that I am the only one that thinks thin filmed Gen 3 still needs additional gain.

My Canon EOS cameras have a feature called "dark frame subtraction" that digitally removes noise. Basically, the sensor is exposed normally, then for the same time without opening the shutter. The noise in the dark frame is analyzed and subtracted (removed) from the actual exposure, producing a very clean image. I wonder if an I2 / digital hybrid could do something similar, on the fly. Maybe a microprocessor could somehow "see" the noise from the intensifier tube, remove it, and then display digitally. Could such a hybrid setup act like a staged unit where the digital portion bumped the display gain up to par on dark nights? Look Ma, no IR. Could thermal fusion be incorporated into the digital display?

More FOV would be really appreciated.

The weight of the PVS 14 really doesn't bother me. Eye strain hasn't been an issue either. Battery life is good, but longer is always better. As for the length of the unit, a more compact design would be a plus. One issue I have is that my right eye is so dominant that I lose the full FOV in the NOD at times (brighter nights). Closing the right eye momentarily get my brain back in drive to see with my left eye thru the NOD correctly. A shorter design would help because my right eye is seeing the NOD housing and distracting me.

Posted: 9/1/2014 7:23:36 PM EDT

[#16]

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Quoted:

PVS 14 Pinnacle user here.

More gain / less noise would still be an big improvement on dark nights. It may be that I am the only one that thinks thin filmed Gen 3 still needs additional gain.

My Canon EOS cameras have a feature called "dark frame subtraction" that digitally removes noise. Basically, the sensor is exposed normally, then for the same time without opening the shutter. The noise in the dark frame is analyzed and subtracted (removed) from the actual exposure, producing a very clean image. I wonder if an I2 / digital hybrid could do something similar, on the fly. Maybe a microprocessor could somehow "see" the noise from the intensifier tube, remove it, and then display digitally. Could such a hybrid setup act like a staged unit where the digital portion bumped the display gain up to par on dark nights? Look Ma, no IR. Could thermal fusion be incorporated into the digital display?

More FOV would be really appreciated.

The weight of the PVS 14 really doesn't bother me. Eye strain hasn't been an issue either. Battery life is good, but longer is always better. As for the length of the unit, a more compact design would be a plus. One issue I have is that my right eye is so dominant that I lose the full FOV in the NOD at times (brighter nights). Closing the right eye momentarily get my brain back in drive to see with my left eye thru the NOD correctly. A shorter design would help because my right eye is seeing the NOD housing and distracting me.

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Hi 1ipschoser,

An interesting aspect - yes, digital can provide an extra "stage" and can do some clever stuff like adjusting "phosphor" persistence on the fly, and well as tracking movement to allow multi-frame integration.

Also an interesting question - about the possibility of digital noise reduction - especially given the real-time nature of the system... I guess it's possible, theoretically, to spot ion strikes as well and maybe remove them - though I guess the challenge is how to remove noise without compromising tactical information. The approach used mostly seems to be to increase the signal and reduce other sources of noise under such very dark conditions. Also, I hear that there are new tube technologies pushing in that direction, but have never seen one.

Some very helpful detail there, thank you - :)

It also seems that the 40-degree limitation is a bit of a theme to the responses... What would you want there? 50 degrees? 60 ? WFOV? Multitube (eg, GPNV ) - Up to about 60 degrees can be achieved in a binocular fashion, but the common area where you can gain depth perception is limited - after than most people use multi-tube such as the GPNVG - though it does leave me wondering what would be considered an improvement there.

Also, increasing FOV tends to move the lens weight to the back of the monocular - the objective can shrink, but the ocular must get larger to maintain eye relieve while increasing field - Some wide-angle lenses can handle up to 80 degrees, but your eye is pretty much attached to them the whole time. I know the US navy was experimenting with different eyepieces and objectives like this, but never found out the results or whether it was a good solution.

Regards

David

Posted: 9/1/2014 10:21:30 PM EDT

[#17]

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Quoted:

Also an interesting question - about the possibility of digital noise reduction - especially given the real-time nature of the system... I guess it's possible, theoretically, to spot ion strikes as well and maybe remove them - though I guess the challenge is how to remove noise without compromising tactical information. The approach used mostly seems to be to increase the signal and reduce other sources of noise under such very dark conditions. Also, I hear that there are new tube technologies pushing in that direction, but have never seen one.

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Quoted:

Also an interesting question - about the possibility of digital noise reduction - especially given the real-time nature of the system... I guess it's possible, theoretically, to spot ion strikes as well and maybe remove them - though I guess the challenge is how to remove noise without compromising tactical information. The approach used mostly seems to be to increase the signal and reduce other sources of noise under such very dark conditions. Also, I hear that there are new tube technologies pushing in that direction, but have never seen one.

How about an intensifier that electronically switches very rapidly between actual gain and, say, 50% gain? The respective outputs could then be feed into a dual channel CPU that takes the noise out of the full gain channel by comparing ion strikes with the 50% channel. Final output would be a digital display. Possible? Would the brain only see the high gain setting if it switched rapidly enough? Could the digital display only show the full gain (or selected gain) channel?

Quoted:
It also seems that the 40-degree limitation is a bit of a theme to the responses... What would you want there? 50 degrees? 60 ? WFOV? Multitube (eg, GPNV ) - Up to about 60 degrees can be achieved in a binocular fashion, but the common area where you can gain depth perception is limited - after than most people use multi-tube such as the GPNVG - though it does leave me wondering what would be considered an improvement there.

A 50% improvement would be huge. Obviously, the more FOV the better.

Posted: 9/1/2014 10:59:44 PM EDT

[#18]

Honestly I am currently fine with the fit and function of current nods for what they are.

Things I would want that are current achievable:

1. Better optics

I come from a photo background and know high end glass when i see it.
Some of the current options out there disappoint me.

I would like to see better MTF on both the objective and ocular lenses, crisper corners and less distortion would make me happy.
Coatings on the ocular lens would also be nice to cut out some glare on the back half in brighter situations.

2. Focus:

On all the NVD's I've used focus is a PITA.

Like I've said before I'm used to high end optics on $6000 lenses.
If I'm paying that much for a NVD i expect some better focus performance on both the ocular and objective lenses.
The way they stick and jump pisses me off when I try to focus and are imho pretty rough.

I want smoother and more accurate focusing and tighter tolerances when it comes to lens housings.

3. Gain:

Like everyone has already stated, more gain the better.

4. Tube Diameter

Bigger the better to a point.
Id like to see a slightly larger tube used, preferably lighter, but a bigger viewable scree would be nice, be it a mm or two.

Thats all i got that is within reason.

Posted: 9/2/2014 10:55:06 AM EDT

[#19]

I'd be the first to admit that some of the technical stuff you wrote about goes a little bit over my head - but from an end-user perspective, I suppose I can do my best to answer some of your questions.

From an end-user perspective, I've been using NV for close to ten years now, mostly AN/PVS-7 models and AN/PVS-14s, with very limited experience with AN/PVS-15s and having "peeped through" ANVIS models, though I just got into the whole personal ownership aspect wherein it's now my investment we're talking about this spring.

Before going directly into the questions, though - I would say that just as a couple of general statements:

a) hey, what would actually be awesome is a set of NODs that worked just like human eyeballs - maximum FOV, "auto-adjust" to lighting conditions, auto focus, and in the size of say a contact lens, or maybe even a pair of eyeglasses. Yes, I know that's far fetched and reaching into the realm of science fiction, and we can't all trade 20 Menthol Kools for a surgical shine job, but hey - if you don't dream big, you can never win big.

b) I think a 50% improvement "all around" seems like a pretty good benchmark, and if you could reduce weight and length by 50% and increase FOV and battery life by 50%, you'd have no complaints anywhere. I think that, unlike the above, is a reasonably attainable goal within the next say ten years of development, though it may not be immediately possible. Of course, a 50% reduction in price would be excellent as well - but that's generally scaled as technology matures.

c) basic durability will always be high on my list - PVS-14s are reasonably durable, but they still can't be "knocked around" the same way, say most reliable combat weapons optics can be - I'd love the kind of durability of an ACOG in a NOD. Going along with that - waterproofing/water resistance - one of the big "turn-offs" for me for something like the ANVIS family is water resistance. I'm not talking necessarily about needing to go diving with NOD, but maybe, say a couple hours at 6 feet - I'd like to have something that I feel comfortable operating if need be in an area that may suffer from the occasional torrential downpour, and something that I wouldn't have to worry about if I say fell into a creek/body of water, and something that I could put in a pouch in a humid environment with lots of water vapor and drizzles and simply not care, and not be afraid to try and use it.

So, on to your questions:

Q1. Image Quality/comfort point-of-view: is the Intensified image tiring? Why (noise, brightness, …)? (Noisiness of the image means more "turbulent”/less stable image ) -

A1. I don't think I have the technical/medical background to sufficiently answer this so I will bypass it. Whatever can be done to make it more comfortable to wear NOD? I say "why not."

Q2. What is the performance improvement that would be a compelling reason to upgrade or change your NVG?

A2. I think this would go back to what I was talking about before, with the overall "50%." I'm compelled by fusion technology, and could definitely see some applications for it, but I'm not necessarily convinced of its necessity... unlike rattlesnakes, we don't have any daytime thermal detection abilities - I think that the better goal is to try to first simply try to give users the same capabilities they have during the day at night - and of course, if you can see as well as you can during the day, just at night - there's no training curve to "learn to use" your new detection abilities. I do think some color/a less monochromatic view through a NOD would be both helpful and very welcome.

Once again, I laud any improvement in performance anywhere - and like many things, I'm sure it will be evolutionary and gradual - but as for how much it would take me to upgrade or change is a harder question - of the priorities I listed earlier, I think I would place FOV and weight in the top priority tier, with length coming in second, and battery life as an incidental concern [relative to the PVS-14]. In other words - if you told me that at the same weight, length, and battery life of the PVS-14 I could have 50% more FOV, that would be compelling. Likewise if you told me that at the same FOV, length, and battery life of the PVS-14, I could have a 50% reduction in weight - this would once again be compelling - if for no other reason than while yes, I'd love more FOV - but I've been trained and am used to what the PVS-14 offers me. It's not that I couldn't use more - but that I'm already used to making do with what I have. If, out of those four catagories, you could improve two of them by 50% (50% of 50%

) it would be a no-brainer.

Q3. What is the added feature that would be a compelling reason to upgrade or change your NVG?

A3. I think this is the one where I might have the most useful input that's not "pipe dreaming" DARPA style about future potential technologies.

What I would like to see is modularity - much more modularity. Since I've already outlined things I might want to see in terms of performance above - once again, any improvement in performance is welcome, but in terms of features, even if you assumed that the performance per se remained identical - keeping in mind my durability and waterproofing concerns - this would make me upgrade in an instant:

The basis would be easily - user - preferably in the field - swappable power supplies. Provide the I2 tube and the associated lenses/electronics, etc. as a self-contained, individual unit with an interface for different power supplies, using perhaps a dovetail with contacts, a cam, and a rubber gusset. The tube housing itself would have no power supply - rather - several different power modules could be made available:

1. Mount only interface - provides nothing more than a mounting system for a helmet mount, and a connection to an external power supply a la ANVIS - benefits - reduced weight "up front" and built-in counterweight by moving power supply entirely
2. Multiple "self contained" power supplies, like the current PVS-14 battery pack, but user swappable in the field, allowing you to use single AA, dual AA, 3V, or CR123, all based on your preferences and what was available. An ancillary benefit of this kind of system is that a user in a "deep cover" or SR capacity (probably using a NiteCap

) could carry multiple power supply modules, and use whatever batteries they could find/carry without worrying as much about specific re-supply
3. Hybrid power supply - basically just a power supply module allowing you to use both self-contained and external power supply
4. Binocular bridge mounts in the same three varieties - self-containted, external power only, and hybrid - folds for storage or "on the fly" switch to monocular solution - essentially an articulared bridge with a single power supply module that could power both tubes, that you could simply "attach" and go from a monocular solution to a binocular solution as the situation dictates, for a slim-line set of binos

All the power supply modules would also contain the activation switch/knob, and a gain control mechanism - auto-gain, like, say, the EOTech, which automatically "turns on" based on abient light conditions, but can also be manually manipulated would be nice here - or one that at very least turns on automatically to, say, 85% gain, as I've run into the situation where a NOD that's been being stored in say a pouch has "self-adjusted" through movement and contact with other items and turned itself down. Meanwhile, the power modules for the dual bridge interfaces and the tubes would be configured so that they could work in concert with a single manual gain knob. Also - and I know that this might be a bit more controversial - but it would be interesting, I think, to see what the practical application of a programmable mount/switch that would at least allow you to select the option of not only an auto-shutoff when the NODs are flipped up, but auto-activation when you swing them down. With a push button mount, you could simply build them all into the same button with an "activate/deactivate" switch.

From a user standpoint, IMHO, this would basically be able to replace with a single "system," at least within the DoD, the AN/PVS-14, AN/PVS-15, AN/PVS-18, and AN/PVS-31 and possibly even the ANVIS family if done correctly in "one fell swoop." "Regular" infantry units could get a "basic" kit that was basically little different than the AN/PVS-14, maybe with both the external and self-contained power modules in a single kit, while more specialized units could get the whole "kit" for binocular and monocular NVGs.

On the commercial market, as the I2 tubes are the most cost intensive component - once again, you could market a single tube "basic" kit, and users that wanted to upgrade to binoculars wouldn't have to buy a whole new system and/or pay for a conversion and give up their ability to use monoculars, nor deal with less than ideal, heavy bridge mounts - they could simply invest in a second tube module and the and the appropriate accessory components to have a purpose designed binocular, and also a second independent power module so that they could "share." Moreover - and now you're getting into more of the realm of the hypothetical, but if you could DoD buy-in and contracts for this kind of plan, you could "load" a lot of the R&D costs into those early contracts and on early adopters, and in the long run have a system that's overall much more affordable than the currently available options.

Speaking of power supplies again, and which will be my final couple of thoughts on this issue - in terms of external power supplies - is there any reason not build this into the mount/shroud interface and thereby eliminate and avoid the whole external wire issue? Certainly, you'd need to waterproof it and figure out what you're going to do about making it durable enough, but it seems, at least, to me, as though it shouldn't be insurmountable.

Going with the same power modules - if your helmet is equipped with a mount that works with a built in power supply, you can bypass to a certain extent the issue of routing wires, plugging them in, etc. - attach the NOD to the mount, and you're immediately "hooked in" to your power supply. With a non-powered mount - it can operate with self-contained power supplies, no muss, no fuss.

Q4. What is the change in image quality/"comfort” of image that would be a compelling reason to upgrade or change your NVG?

A4. The most annoying thing that I have experienced "comfort wise," though it has little impact on use, perhaps - is that after many hours in near complete darkness under "green eyes," when I get back into white light, everything seems to have a weird reddish-purplish "tinge" to it for a little while - I'm assuming because of my brain/eyes upping the "red balance" after seeing so much green for so long. A way to get rid of that might be nice.

I don't know if that would compell me to change or upgrade my NODs independent of other improvements - but it would be nice.

Q5. What are the other improvements expected from Night Vision Goggles?

A5. I think I've more or less covered this all throughout...

~Augee

Posted: 9/3/2014 7:03:05 PM EDT

[#20]

Quote History

Quoted:

I'd be the first to admit that some of the technical stuff you wrote about goes a little bit over my head - but from an end-user perspective, I suppose I can do my best to answer some of your questions.

From an end-user perspective, I've been using NV for close to ten years now, mostly AN/PVS-7 models and AN/PVS-14s, with very limited experience with AN/PVS-15s and having "peeped through" ANVIS models, though I just got into the whole personal ownership aspect wherein it's now my investment we're talking about this spring.

Before going directly into the questions, though - I would say that just as a couple of general statements:

a) hey, what would actually be awesome is a set of NODs that worked just like human eyeballs - maximum FOV, "auto-adjust" to lighting conditions, auto focus, and in the size of say a contact lens, or maybe even a pair of eyeglasses. Yes, I know that's far fetched and reaching into the realm of science fiction, and we can't all trade 20 Menthol Kools for a surgical shine job, but hey - if you don't dream big, you can never win big.

b) I think a 50% improvement "all around" seems like a pretty good benchmark, and if you could reduce weight and length by 50% and increase FOV and battery life by 50%, you'd have no complaints anywhere. I think that, unlike the above, is a reasonably attainable goal within the next say ten years of development, though it may not be immediately possible. Of course, a 50% reduction in price would be excellent as well - but that's generally scaled as technology matures.

c) basic durability will always be high on my list - PVS-14s are reasonably durable, but they still can't be "knocked around" the same way, say most reliable combat weapons optics can be - I'd love the kind of durability of an ACOG in a NOD. Going along with that - waterproofing/water resistance - one of the big "turn-offs" for me for something like the ANVIS family is water resistance. I'm not talking necessarily about needing to go diving with NOD, but maybe, say a couple hours at 6 feet - I'd like to have something that I feel comfortable operating if need be in an area that may suffer from the occasional torrential downpour, and something that I wouldn't have to worry about if I say fell into a creek/body of water, and something that I could put in a pouch in a humid environment with lots of water vapor and drizzles and simply not care, and not be afraid to try and use it.

So, on to your questions:

Q1. Image Quality/comfort point-of-view: is the Intensified image tiring? Why (noise, brightness, …)? (Noisiness of the image means more "turbulent”/less stable image ) -

A1. I don't think I have the technical/medical background to sufficiently answer this so I will bypass it. Whatever can be done to make it more comfortable to wear NOD? I say "why not."

Q2. What is the performance improvement that would be a compelling reason to upgrade or change your NVG?

A2. I think this would go back to what I was talking about before, with the overall "50%." I'm compelled by fusion technology, and could definitely see some applications for it, but I'm not necessarily convinced of its necessity... unlike rattlesnakes, we don't have any daytime thermal detection abilities - I think that the better goal is to try to first simply try to give users the same capabilities they have during the day at night - and of course, if you can see as well as you can during the day, just at night - there's no training curve to "learn to use" your new detection abilities. I do think some color/a less monochromatic view through a NOD would be both helpful and very welcome.

Once again, I laud any improvement in performance anywhere - and like many things, I'm sure it will be evolutionary and gradual - but as for how much it would take me to upgrade or change is a harder question - of the priorities I listed earlier, I think I would place FOV and weight in the top priority tier, with length coming in second, and battery life as an incidental concern [relative to the PVS-14]. In other words - if you told me that at the same weight, length, and battery life of the PVS-14 I could have 50% more FOV, that would be compelling. Likewise if you told me that at the same FOV, length, and battery life of the PVS-14, I could have a 50% reduction in weight - this would once again be compelling - if for no other reason than while yes, I'd love more FOV - but I've been trained and am used to what the PVS-14 offers me. It's not that I couldn't use more - but that I'm already used to making do with what I have. If, out of those four catagories, you could improve two of them by 50% (50% of 50%

) it would be a no-brainer.

Q3. What is the added feature that would be a compelling reason to upgrade or change your NVG?

A3. I think this is the one where I might have the most useful input that's not "pipe dreaming" DARPA style about future potential technologies.

What I would like to see is modularity - much more modularity. Since I've already outlined things I might want to see in terms of performance above - once again, any improvement in performance is welcome, but in terms of features, even if you assumed that the performance per se remained identical - keeping in mind my durability and waterproofing concerns - this would make me upgrade in an instant:

The basis would be easily - user - preferably in the field - swappable power supplies. Provide the I2 tube and the associated lenses/electronics, etc. as a self-contained, individual unit with an interface for different power supplies, using perhaps a dovetail with contacts, a cam, and a rubber gusset. The tube housing itself would have no power supply - rather - several different power modules could be made available:

1. Mount only interface - provides nothing more than a mounting system for a helmet mount, and a connection to an external power supply a la ANVIS - benefits - reduced weight "up front" and built-in counterweight by moving power supply entirely

2. Multiple "self contained" power supplies, like the current PVS-14 battery pack, but user swappable in the field, allowing you to use single AA, dual AA, 3V, or CR123, all based on your preferences and what was available. An ancillary benefit of this kind of system is that a user in a "deep cover" or SR capacity (probably using a NiteCap

) could carry multiple power supply modules, and use whatever batteries they could find/carry without worrying as much about specific re-supply

3. Hybrid power supply - basically just a power supply module allowing you to use both self-contained and external power supply

4. Binocular bridge mounts in the same three varieties - self-containted, external power only, and hybrid - folds for storage or "on the fly" switch to monocular solution - essentially an articulared bridge with a single power supply module that could power both tubes, that you could simply "attach" and go from a monocular solution to a binocular solution as the situation dictates, for a slim-line set of binos

All the power supply modules would also contain the activation switch/knob, and a gain control mechanism - auto-gain, like, say, the EOTech, which automatically "turns on" based on abient light conditions, but can also be manually manipulated would be nice here - or one that at very least turns on automatically to, say, 85% gain, as I've run into the situation where a NOD that's been being stored in say a pouch has "self-adjusted" through movement and contact with other items and turned itself down. Meanwhile, the power modules for the dual bridge interfaces and the tubes would be configured so that they could work in concert with a single manual gain knob. Also - and I know that this might be a bit more controversial - but it would be interesting, I think, to see what the practical application of a programmable mount/switch that would at least allow you to select the option of not only an auto-shutoff when the NODs are flipped up, but auto-activation when you swing them down. With a push button mount, you could simply build them all into the same button with an "activate/deactivate" switch.

From a user standpoint, IMHO, this would basically be able to replace with a single "system," at least within the DoD, the AN/PVS-14, AN/PVS-15, AN/PVS-18, and AN/PVS-31 and possibly even the ANVIS family if done correctly in "one fell swoop." "Regular" infantry units could get a "basic" kit that was basically little different than the AN/PVS-14, maybe with both the external and self-contained power modules in a single kit, while more specialized units could get the whole "kit" for binocular and monocular NVGs.

On the commercial market, as the I2 tubes are the most cost intensive component - once again, you could market a single tube "basic" kit, and users that wanted to upgrade to binoculars wouldn't have to buy a whole new system and/or pay for a conversion and give up their ability to use monoculars, nor deal with less than ideal, heavy bridge mounts - they could simply invest in a second tube module and the and the appropriate accessory components to have a purpose designed binocular, and also a second independent power module so that they could "share." Moreover - and now you're getting into more of the realm of the hypothetical, but if you could DoD buy-in and contracts for this kind of plan, you could "load" a lot of the R&D costs into those early contracts and on early adopters, and in the long run have a system that's overall much more affordable than the currently available options.

Speaking of power supplies again, and which will be my final couple of thoughts on this issue - in terms of external power supplies - is there any reason not build this into the mount/shroud interface and thereby eliminate and avoid the whole external wire issue? Certainly, you'd need to waterproof it and figure out what you're going to do about making it durable enough, but it seems, at least, to me, as though it shouldn't be insurmountable.

Going with the same power modules - if your helmet is equipped with a mount that works with a built in power supply, you can bypass to a certain extent the issue of routing wires, plugging them in, etc. - attach the NOD to the mount, and you're immediately "hooked in" to your power supply. With a non-powered mount - it can operate with self-contained power supplies, no muss, no fuss.

Q4. What is the change in image quality/"comfort” of image that would be a compelling reason to upgrade or change your NVG?

A4. The most annoying thing that I have experienced "comfort wise," though it has little impact on use, perhaps - is that after many hours in near complete darkness under "green eyes," when I get back into white light, everything seems to have a weird reddish-purplish "tinge" to it for a little while - I'm assuming because of my brain/eyes upping the "red balance" after seeing so much green for so long. A way to get rid of that might be nice.

I don't know if that would compell me to change or upgrade my NODs independent of other improvements - but it would be nice.

Q5. What are the other improvements expected from Night Vision Goggles?

A5. I think I've more or less covered this all throughout...

~Augee

View Quote

Hi Augee,

Just so I understand the idea, you're talking about making the battery compartment modular right? Kind of how the PVS-14 comes with a CR123, AA+AA or AA battery option, but something you could easily change to whatever battery you wanted without needing a screwdriver ? So anything from a small handheld dynamo/battery ( when there's no battery ) through to button cells, lithiums, even direct contacts to external batteries -

This rather than a socket and external battery adapter right?

An interesting idea - I don't think I've seen that one before :) I like that idea -

Regards

David

Posted: 9/3/2014 11:23:25 PM EDT

[#21]

Quote History

Quoted:
Hi Augee,

Just so I understand the idea, you're talking about making the battery compartment modular right? Kind of how the PVS-14 comes with a CR123, AA+AA or AA battery option, but something you could easily change to whatever battery you wanted without needing a screwdriver ? So anything from a small handheld dynamo/battery ( when there's no battery ) through to button cells, lithiums, even direct contacts to external batteries -

This rather than a socket and external battery adapter right?

An interesting idea - I don't think I've seen that one before :) I like that idea -

Regards
David

View Quote

I think we're on the same page.

Yes - basically what I'm talking about is something like the PVS-14 housing with the various different battery/power supply configurations - but making those modular so that they could be replaced and/or changed in the field without tools.

This would allow for multiple different configurations and options using the same image intensifier tubes and basic hardware, ranging from a self-contained, handheld monocular, to a lightweight helmet mounted monocular with an external battery pack, to a "full service" binocular setup that can be used with both an external battery pack and a self-contained battery.

For example there's the "debate" between dual AA and single AA modules for PVS-14s - single AA units are lighter, but dual AAs have a longer runtime. Currently it would require a screwdriver, a soldering iron, and probably a well lit workbench to change from one to the other. If you made the power supply modular - if you knew you were only going to need the NODs for a short duration and wanted to keep the weight to a minimum, you could snap in the single AA module, while if you were going to need them for a longer duration, you could snap in the dual AA module.

In the same vein - if you've got a single PVS-14 now and wanted to upgrade to binoculars none of your options are really very great or cost effective. You could get a second PVS-14 and a bridge mount - but you'd end up with an unnecessarily heavy unit, while if you decided to convert your PVS-14 into a binocular configuration you've pretty much given up the option to run a monocular ever again. The only really effective option you have is to buy a second set of binoculars for ~$7,000, which can be prohibitively expensive for a lot of private users.

With modular power supply modules you could simply buy a second tube and a bridge mount - you can snap them together and have a set of effective binoculars, or you can snap in the individual power supply and go back to a monocular. Buy a second independent power supply and you can "bring a friend" and both have monoculars, while still having a decent set of binoculars for when you're on your own, or if your buddy has their own NOD.

And like I said, it could be just as beneficial for military applications. A CR123 module could allow you to run a single battery type for your weapon light, LAM, and NODs. An AA module could allow you to go on SR or "low vis" operations and never worry about whether or not you're going to be able to find more batteries in some shit hole part of the world. Plus - with some users issued both a monocular and binocular NVD - you could cut down on one I2 tube per end-user, which, in the aggregate could lead to a significant cost savings that could be used to purchase other mission essential equipment. Moreover, if you could get the aviators to buy in to this scheme, rather than having AN/PVS-7s, AN/PVS-14s, AN/PVS-15s, AN/PVS-18s, AN/PVS-31s, AN/AVS-6s, and AN/AVS-9s all in the system, you could have a single basic module, with different power module accessories for different applications, thereby cutting down the number and type of different kinds of spare parts and training for maintainers, streamlining and simplifying the supply and procurement system, saving overhead costs, and generally making things more efficient.

It's also got room to grow, too - as technology matures, you could figure out how to make it work with a dual thermal/I2 setup - you could have folded optic tube systems that could use the same power supply, perhaps even quad tube modules, etc.

Basically the NVG version of the AR15 is what I'm getting at.

~Augee

Posted: 9/4/2014 2:49:38 AM EDT

[#22]

How does the glass/optics in the AN/PVS-18 and MUM-14 compare to the AN/PVS-14? Which one is higher quality?

Posted: 9/5/2014 10:09:17 AM EDT

[#23]

Quote History

Quoted:

How does the glass/optics in the AN/PVS-18 and MUM-14 compare to the AN/PVS-14? Which one is higher quality?

View Quote

"Higher Quality"? Probably the AN/PVS-18... As it probably uses an aviation cell.

But the PVS-14 lens is faster, and probably has a higher resolution image, but suffers from DoF more than either.

Mum? Excellent glass, but slower than PVS-14 and better focus over a distance -

Generally, I'd choose a PVS-14 lens out of all of them -

Regards

David

Posted: 9/5/2014 4:44:44 PM EDT

[#24]

Quote History

Quoted:
Mum? Excellent glass, but slower than PVS-14 and better focus over a distance -

View Quote

Wait a second, aren't they both f/1.2? That number is everything I understand about the issue, so no surprise if there's more to it though.

Posted: 9/5/2014 7:41:41 PM EDT

[#25]

Quote History

Quoted:
Wait a second, aren't they both f/1.2? That number is everything I understand about the issue, so no surprise if there's more to it though.

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:

Mum? Excellent glass, but slower than PVS-14 and better focus over a distance -

Wait a second, aren't they both f/1.2? That number is everything I understand about the issue, so no surprise if there's more to it though.

In the article, it explains why they are so different - There are two numbers that are important - The T number and F number -

F number is the ratio of lens aperture to lens focal length, and describes a ratio, but doesn't adequately reflect what light does while it's inside the lens - Light can be lost inside the lens due to many issues, including reflection and absorption ( usually through internal aperture restriction ) -It is this that affects how much light is actually transmitted through the lens ( T number ).

The T number aspires to the F number, but can never achieve it - however the closer it comes, the more light that will get through the lens.

A higher T number ( higher = worse ) will mean less effective light and is the true measure of how good the lens is - It stands for "Transmission" and is like a F number corrected for defect - However the aperture aspect is also quite important. MUM's have a higher T number, so the effect to the user is to cause a wider depth of field - A PVS-14 focussed at infinity is blurry around 8m... While a MUM is still pretty sharp right up to about 4m... Of course, this is at the cost of relative performance...

The MUM lenses are still very good though - just not as efficient at the PVS-14 lenses.

Regards

David

Posted: 9/5/2014 9:35:10 PM EDT

[#26]

Quote History

Quoted:

In the article, it explains why they are so different - There are two numbers that are important - The T number and F number -

F number is the ratio of lens aperture to lens focal length, and describes a ratio, but doesn't adequately reflect what light does while it's inside the lens - Light can be lost inside the lens due to many issues, including reflection and absorption ( usually through internal aperture restriction ) -It is this that affects how much light is actually transmitted through the lens ( T number ).

The T number aspires to the F number, but can never achieve it - however the closer it comes, the more light that will get through the lens.

A higher T number ( higher = worse ) will mean less effective light and is the true measure of how good the lens is - It stands for "Transmission" and is like a F number corrected for defect - However the aperture aspect is also quite important. MUM's have a higher T number, so the effect to the user is to cause a wider depth of field - A PVS-14 focussed at infinity is blurry around 8m... While a MUM is still pretty sharp right up to about 4m... Of course, this is at the cost of relative performance...

The MUM lenses are still very good though - just not as efficient at the PVS-14 lenses.

Regards
David

View Quote View All Quotes

View All Quotes

Quote History

Quoted:

Quoted:
Wait a second, aren't they both f/1.2? That number is everything I understand about the issue, so no surprise if there's more to it though.

In the article, it explains why they are so different - There are two numbers that are important - The T number and F number -

F number is the ratio of lens aperture to lens focal length, and describes a ratio, but doesn't adequately reflect what light does while it's inside the lens - Light can be lost inside the lens due to many issues, including reflection and absorption ( usually through internal aperture restriction ) -It is this that affects how much light is actually transmitted through the lens ( T number ).

The T number aspires to the F number, but can never achieve it - however the closer it comes, the more light that will get through the lens.

A higher T number ( higher = worse ) will mean less effective light and is the true measure of how good the lens is - It stands for "Transmission" and is like a F number corrected for defect - However the aperture aspect is also quite important. MUM's have a higher T number, so the effect to the user is to cause a wider depth of field - A PVS-14 focussed at infinity is blurry around 8m... While a MUM is still pretty sharp right up to about 4m... Of course, this is at the cost of relative performance...

The MUM lenses are still very good though - just not as efficient at the PVS-14 lenses.

Regards
David

Thanks for the (re)explanation, now checking the article again and you do indeed say that about the MUM vs PVS-14 (and everything about the T number), sorry. I thought when the focal length & objective lens size are the same they perform the same, but of course all that's inside have a say too. Do you have an idea in percentage of the light loss of MUM versus PVS-14?

Posted: 9/6/2014 3:43:29 AM EDT

[#27]

Expounding a little on the swappable power packs (I'm envisioning a camera hot shoe kinda set up). But the power sully integrated into the shroud is intriguing. I'm thinking having a battery mounted horizontally (like the EoTech XPS's) on the top of the shroud, low profile, out of the way and use an ANVIS style ball detent to deliver the power to the NOD. Or have one batt on either side of the shroud mounted parallel.

Posted: 9/6/2014 11:06:38 AM EDT

[#28]

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Quoted:

Thanks for the (re)explanation, now checking the article again and you do indeed say that about the MUM vs PVS-14 (and everything about the T number), sorry. I thought when the focal length & objective lens size are the same they perform the same, but of course all that's inside have a say too. Do you have an idea in percentage of the light loss of MUM versus PVS-14?

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Wait a second, aren't they both f/1.2? That number is everything I understand about the issue, so no surprise if there's more to it though.

In the article, it explains why they are so different - There are two numbers that are important - The T number and F number -

F number is the ratio of lens aperture to lens focal length, and describes a ratio, but doesn't adequately reflect what light does while it's inside the lens - Light can be lost inside the lens due to many issues, including reflection and absorption ( usually through internal aperture restriction ) -It is this that affects how much light is actually transmitted through the lens ( T number ).

The T number aspires to the F number, but can never achieve it - however the closer it comes, the more light that will get through the lens.

A higher T number ( higher = worse ) will mean less effective light and is the true measure of how good the lens is - It stands for "Transmission" and is like a F number corrected for defect - However the aperture aspect is also quite important. MUM's have a higher T number, so the effect to the user is to cause a wider depth of field - A PVS-14 focussed at infinity is blurry around 8m... While a MUM is still pretty sharp right up to about 4m... Of course, this is at the cost of relative performance...

The MUM lenses are still very good though - just not as efficient at the PVS-14 lenses.

Regards

David

Thanks for the (re)explanation, now checking the article again and you do indeed say that about the MUM vs PVS-14 (and everything about the T number), sorry. I thought when the focal length & objective lens size are the same they perform the same, but of course all that's inside have a say too. Do you have an idea in percentage of the light loss of MUM versus PVS-14?

PVS-14 T-number is around 1.3, so I'd guess the MUM is around 1.5 to 1.6 - I did measure it some time ago, but don't recall the exact figure, so that's a very hazy memory.

David

Posted: 9/6/2014 11:07:47 AM EDT

[#29]

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Expounding a little on the swappable power packs (I'm envisioning a camera hot shoe kinda set up). But the power sully integrated into the shroud is intriguing. I'm thinking having a battery mounted horizontally (like the EoTech XPS's) on the top of the shroud, low profile, out of the way and use an ANVIS style ball detent to deliver the power to the NOD. Or have one batt on either side of the shroud mounted parallel.

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An interesting idea...

Though any reason the power and batteries wouldn't be on the rear of the helmet? Back there, they do offset weight a little -

David

Posted: 9/6/2014 11:18:51 AM EDT

[#30]

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Quoted:
PVS-14 T-number is around 1.3, so I'd guess the MUM is around 1.5 to 1.6 - I did measure it some time ago, but don't recall the exact figure, so that's a very hazy memory.

David

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So would I be correct by saying PVS-14 light transmission is around 77% and MUM 66%?

Those numbers look bad to me who don't know much about the matter, but by having a huge f/1.0 lens and T as close to that as possible we would be close to 90% levels, right? To compensate for such percentages with a better tube would be expensive.

Posted: 9/6/2014 9:19:02 PM EDT

[#31]

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Quoted:
So would I be correct by saying PVS-14 light transmission is around 77% and MUM 66%?

Those numbers look bad to me who don't know much about the matter, but by having a huge f/1.0 lens and T as close to that as possible we would be close to 90% levels, right? To compensate for such percentages with a better tube would be expensive.

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Quoted:

PVS-14 T-number is around 1.3, so I'd guess the MUM is around 1.5 to 1.6 - I did measure it some time ago, but don't recall the exact figure, so that's a very hazy memory.

David

So would I be correct by saying PVS-14 light transmission is around 77% and MUM 66%?

Those numbers look bad to me who don't know much about the matter, but by having a huge f/1.0 lens and T as close to that as possible we would be close to 90% levels, right? To compensate for such percentages with a better tube would be expensive.

Well, I'm not sure of your calculations, since I don't know what numbers you started with, and the F-number and T-number do very slightly for different lenses, but 78% looks about right for a PVS-14... So I'd say your T-number for the MUM would be around where I'd expect it -

Back when it made a huge difference, in the PVS-5C, the F-number was around 1.05 ! And the T-number was fairly close - though I can't recall it exactly -

That's probably because it did make a big difference when the PC was around 350 at best, and these were for aviation ( I think the resolution was heading towards 40 lp/mm in later models ) - So the lenses were better and likely cost more as a result.

Gen3 has a huge gain, so compromises can be made elsewhere but both lenses are still very fast - More that suited to military applications - and that allows focus on other aspects such as MTF through the lenses and correcting any aberration.

So the numbers are actually good - it's just that when you look at them the first time, they seem bad.... But keep in mind a good MX11769 tube has a gain of around 70,000 but the PVS-14 has a system gain of around 7000... That's a HUGE loss - an order of magnitude - so 90% of losses through inefficiency... And then people go whacking 3x afocals on them, and the loss is now about 94% or something bad like that... Hang on, let's chuck it in a 6x F2.0 riflescope with a huge ocular and lots of eye relief... Now your losses are heading towards 99%..... Or, to rephrase it, 1 to 2% efficiency...

Now those numbers are scary... Where to find them? Some cheaper riflescopes... I won't mention names... But hey, they do work right! People use them without ever considering the losses and how that effects night-time use and operation under NL6.... Or in simple talk, check out your PVS-14 performance next to a 6x riflescope performance on a dark night under NL5 or NL6... Then you can just see the difference - the riflescope works very badly.

There's a reason some of us covet the PVS-4 with a good lens so much, and in understanding the maths behind it, or having used them, you can see why we don't mind the extra weight of that big cat lens, even without the magnification :)

So, put in context, that MUM-14 lens losing 34 percent of the light? Sure, it's bad, but it's not *that* bad.... 66% transmission is WAY better than 2%.... :) It's all about perspective.

BTW, this thread brought up the excellent idea of using a single lens, without correction, and focussed to infinity. Very light, very large, very high F-number... Digitally processed image to remove noise and focal issues and aberration... And with a bright image through the monocular since you can add more light to a screen without adding noise... Suddenly, those losses can be reduced greatly, and it's a whole new generation of equipment... Maybe they'll skip Gen4 and go straight to Gen5 :)

Regards

David

Posted: 9/6/2014 9:45:48 PM EDT

[#32]

I suppose they could go on the back, but I hate wires hanging everywhere to get snagged on things. Yeah the weight would still be up front, but at least not on the object cantilevered out in front of your face, a little closer to a center of gravity point.

Posted: 9/7/2014 7:05:14 PM EDT

[#33]

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I suppose they could go on the back, but I hate wires hanging everywhere to get snagged on things. Yeah the weight would still be up front, but at least not on the object cantilevered out in front of your face, a little closer to a center of gravity point.

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I think you could still mount the power supply on the back of the helmet without having to have loose or hanging wires - particularly if you built it into the shroud.

I would envision something that might look similar to the Revision shroud and route the wires through/underneath ARC rails and plugged into a battery back on the rear of the helmet where it could continue to serve as a counterweight, or even something like a ratchet strap style mount that routed the wires over the top of the helmet.

IMHO, external wires in general are the way they are because they're something of an afterthought. If it was all part of a purpose built setup with a "powered" shroud, you could integrate the wires into a low profile, no snag design.

~Augee

Posted: 9/21/2014 8:47:10 AM EDT

[#34]

Thank you to everyone who participated in answering these questions - it is very much appreciated -

Just a quick question though in case it resonates with any of the participants - no one mentioned anything like adjustment of the J-arm or mount effectiveness of the monocular to allow multi-role use ( eg, Rifle and head mounted )? I know such issues have come up in the past - but neither were mentioned in the responses - ?

Thanks

David

Posted: 9/22/2014 10:29:34 AM EDT

[#35]

Q1. Image Quality/comfort point-of-view: is the Intensified image tiring? Why (noise, brightness, …)? (Noisiness of the image means more "turbulent”/less stable image ) - I am happy with the image as is for the most part. I like having gain control if viewing for long periods to tone down the brightness some and make it easier on the eyes. I also don't like ion strikes but you already knew that.

Q2. What is the performance improvement that would be a compelling reason to upgrade or change your NVG? Resolution improvements or maybe better contrast. I also like the idea of a separate power supply on tubes. I hate to see tubes go in the trash over a blown power supply. Don't know exactly how that would best be achieved but if the power supply was modular many tubes could be saved

Q3. What is the added feature that would be a compelling reason to upgrade or change your NVG? A affordable thermal add on. If you can convince them to bring back the Gen 3+1 25mm tube I would be a buyer !!

Q4. What is the change in image quality/"comfort” of image that would be a compelling reason to upgrade or change your NVG? More contrast would be nice but I already said that. Lighter weight is always appreciated. The wobble is annoying but I don't run much with them. The wobble is a issue when I am driving the boat and hitting waves. Some newer mounts have solved this but at a high cost to own.

As a guide, consider what the biggest issues are that you are currently experiencing. Do you find NV goggles tiring to use? Do you struggle seeing objects deep in shadows on dark nights? Do you find the range of your goggles just isn't enough, especially without adding more light? Are they too heavy? Do they use batteries too quickly? Are they too heavy? Do they fit correctly? Do they wobble when you run? These individual questions are rhetorical, but should assist in answering the four above questions.

And, if you've thought the above through and know what you want, without limitations, a bonus question -

Q5. What are the other improvements expected from Night Vision Goggles? Bring back the 3+1

I would also like to see a factory CR123 lower for the 14. I know the aftermarket shell was available awhile back but it seems to have disappeared. Ed also said the new ITT Everest tube won't work with a dual battery lower so that may be an issue (don't know why it won't work but Ed said it won't).

I would also like to see a C mount PVS-14 but I know I will never get my wish.

[ARCHIVED THREAD] - Optical, Aesthetic and Ergonomic properties of Night Vision Monoculars - August Questions.

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