I have a MUM that I bought in 2006 or so, not sure what Omni contract the tube was but specs were 64lpmm with a SNR of 29.1, which is pretty good. Although I never had a chance to use them side by side; I always though it was on par with the ANVIS I use professionally. I used it a bunch over the years and was pretty happy with it - minus the GD head crusher mount.

Either way I always keep an eye on the EE here and at other sites just as kind of a hobby and recently snagged a smoking deal on a PVS-14 WP L3 tube with specs that were insane (72lpmm 38SNR) assembled by a reputable builder.

Got it the other day and after hours of waiting anxiously for sunset, put it up to my eye expecting to get my socks blown off and...   It's about the same, but white.

Got the 'ol MUM out and compared them side by side. WP has a slightly brighter image and it appears to have a more uniform clarity toward the edges of the tube, but the resolution of the images was almost exactly the same. There is nothing I could see through the WP that I couldn't through the MUM. If it wasn't for the color I doubt you'd even be able to tell them apart.

Still happy with the deal I got because it came with a bunch of other shit, but it really put into perspective that a step increase in resolution (64 to 72) and an increase of over 8 in SNR was barely noticeable (other specs were very good as well).  Probably won't upgrade my shit any time soon based off of this knowledge.

Am I the only one who has experienced this?

My situation is somewhat similar. I have an Armasight gen3 pvs-14 with an ITT tube, SnR of 29.9 and Res of 64 lp/mm and a couple of gen2 pvs-14's. One from Armasight with is their HD(Photonis) model, and a NGI gen2+ pvs-14(also apparently Photonis) and they both keep up pretty well with the gen3 in all but the darkest conditions. The resolution is noticeably better on the gen3,  but not in a HOLY SHIT kind of way.

Tag for info.  I've been wondering if the WP was worth the extra thousand bucks over the Omni VIII

Ive been telling you guys exactly this for over a decade...

Consider a old school pvs5 had 30-40ish lp/mm and 12-15SNR... at BEST modern tubes are 2x as good.

If my calculations are correct a person using 26mm lens like in a PVS-14 cannot see lines on a Johnson chart past about 60lp/mm in a perfect world unless your vision happens to be better than 20/20. That said the MTF will have a negative effect on this so as to give and advantage to a higher lp/mm. In other words a tube with a higher lp/mm (60) will not gain you much in resolution however it may help improve the signal/noise number some.

Also to give you some prospective on S/N the difference between a S/N of say 25 and one of 30 is the same as using a light source of 25 LED's and comparing it to a light source of 30 LED's (all LED's being the same type and applied voltage). You are not going to see a lot of difference.

IMHO, specs are important...

...to a point.

I think guys get a little more hung up on specs than is strictly necessary, because at the end of the day, they're the easiest thing to compare, particularly on the internet and/or without seeing the tubes for yourself and tube photographs don't necessarily capture the "actual image" through a tube very well. The specs become a "common language" to compare tubes, especially considering that some folks simply haven't seen enough different tubes to have a realistic frame of reference for comparison.

On the one hand, I still recommend getting the best tube you can afford because... well, why not? But at the same time, I've also run dual monocular setups with one OMNI VII and one OMNI III tube, and been able to work with it just fine.

At the same time, there are some folks who can't seem to tell the difference between a standard definition television/broadcast or HDTV. Vision can be an awfully subjective thing, and sometimes it comes back to the "mind teaser" question of "how do I know that what green looks like to me looks the same as it looks to you?"

Also, depending on what you're doing, the environment, even the quality/condition of lenses you're using, the spec differences may not make that much of a practical difference, someone doing short range work in generally well lit conditions may not notice as much of a difference as someone doing longer range surveillance looking for camouflaged enemies.

~Augee

Learned this decades ago.

2 X the money does not make the product 2 X better.

Ask a FN owner who paid $2,500 for a 5.56 bullet launcher if it has 5 times the range, or makes bad guys 5 times deader. Not.

Ask a Rolex owner if his watch keeps time 200 X better than a $400 Seiko, or is 200 X tougher than a G Shock. Not.

Doubling the price never makes the product twice as good. If anything it's only half as good again, and if you double the price again, then only a quarter better. You reach a point of diminishing returns.

Hillary paid more money on the election than Trump and look what happened there. Describing quality by a numerical quantity of money is not a valid indicator of its excellence.

I’ve been aching to upgrade my Omni 7 AG thin filmed tubes to L3 WP filmless but lately I’ve been wondering the same thing.

Maybe I’ll just be happy with what I have. For once.

There very much is a point of diminishing returns. Looking at the performance of the tube and its optical system is only half the problem as there's no point in designing a monocular that vastly surpasses the actual performance of the eye under realistic conditions.

Quick glance suggests that the visual acuity of the eye is about 1.2-1.8 arcminutes per line pair under optimal conditions (bright light). Converting 1.8 arcminutes per line pair to radians (5.2e-4 radians per line pair) and assuming a focal length of 22mm for the eye, the effective resolution is 11.4 microns per line pair or 87lp/mm. This is under optimal conditions with the retina receiving lots of light and the eye operating in its photopic vision regime. Looking thru a NV monocular, even under a full moon, does not satisfy this condition and the eye is operating closer to or well in the mesopic vision regime where visual acuity degrades. How much? One reference I found suggests a factor of two or worse (40-45lp/mm effective).

Breaking up due to character limit per post

Working backwards, the typical 64lp/mm resolution figure for tubes is pretty much a sweet spot in terms of system optimization and probably wasn't arrived at by chance. If the objective is assumed to be an ideal f/1.2 lens and the peak response of the tube is assumed to be 800nm, the diffraction limited spot size for such an ideal lens is about 2.5 microns. For a 64lp/mm tube, the characteristic size of the "bright" line in said line pair would be 1mm/128 or about 7.5 microns. Considering no lens is ideal (and often very non-ideal), the front end of the night vision system is already approaching physical limits. On the downstream side of the tube, the eyepiece is similarly diffraction limited though with a somewhat more favorable minimum theoretical spot size due to the shorter wavelength (500nm). Those two lenses work together to degrade the image further.

Numbers crunched by people who have looked into this far more carefully than I have suggest that the resolution of a typical 64lp/mm tube is degraded to about 40-50lp/mm when real optical elements on each side of the tube are considered. Look at that! The overall resolution of the entire system corresponds to the effective resolution of the human eye operating at illumination levels encountered at the output of the NVD.

Looking at tube SNR on a log scale is also insightful and shows the point of diminishing returns that would be expected and is observed in practice.

FWIW.... just because your tube specs are amazing, doesn't mean your eyes are too.

Good point, in this case I'm at 20/20 with no other issues.

Try running the test in a very dark room with no IR illumination on both units. It should be dark enough you see a lot of scintillation. Does the higher SNR unit show better clarity on objects and with less scintillation? It should.. I'm curious what you find. I've been curious myself at what point the specs have a large diminishing return.

Comparing a MUM and a PVS-14 may be comparing apples and oranges, the objective lenses will effect the results.

Tried it the other night, just did it again now with the intent of posting pictures but I don't think they were very representative of the images.

Level of discernable detail at objects in my basement using only ambient light (30 yards long, with almost no visible illum) was almost identical. More scintillation in the old tube but it may just be more noticeable over the green background too.

EDIT: I fucked up, been using the MUM for so long I forgot I had manual gain. Turned it up a bit and tried again, WP has a brighter image with marginally more detail, scintillation is a toss up. I did use it the other night however.

So am I correct in assuming that it’s a better image but not necessarily worth thousands to upgrade if we already have good gen 3 tubes.

I think this is the meat of the argument. There's going to be certain situations where the specs matter. In the case described above, it sounds like that could matter a lot for certain individuals. If you're on watch and someone can get essentially twice as close to you with "good" specs as opposed to how close they can get with better than good specs, it might be opening yourself up to danger that's directly caused by the capabilities of your equipment.

I think Sam nailed it.  If you have an area where you can see out a 1/2 klick, then yeah, damn right the specs matter.  But if you are in a heavily wooded area where detection ranges are typically 100m or less, then perhaps not.  I have been scoping things out the last couple of weeks with some new kit I've added to the mix, and I have to laugh because conditions have been precisely as Sam described, clear skies, 1/2-full moon, and pretty much nothing visible past 100m due to brush and trees.  So I'm probably sitting here going man, this old -14 (going on 11 years) is the shit.

So I'd have to say that specs do matter, and the new stuff is the shit.  I don't think that is in question; it's whether you really need it, and/or can afford it.

If you are happy sitting in your little patch of the world, and your NV is looking good, then drive on.  If not, well then consider an upgrade.

This conversation reminds me of the Russian POV, where in the past they have been envious of western tech, so they made up excuses why it didn't matter.  "Perfect is the enemy of good enough" and so forth.

Specs always matter. Even if your eyes can’t differentiate the difference that doesn’t mean there isn’t a difference. It may take an ideal situation but a better spec tube will perform.... better.

I don't want to pay for something that I can't use. Have you ever been to the eye doctor and been ask to read the lines on the eye chart? There comes a point where you can't read the line. You know the line of letters is clear but they look fuzzy and you can't read it. Same thing holds true for optics if you can't see a differences why buy it?
Back in the 1970's they would sale audio amps spec. to 40 or 50 KHZ, a human can't hear much passed 20 but they were willing to tell you that the sound was far better and as one would expect the price was far higher too. But if it's your money go for it.

Hence Sam's comment about 20/10 vision.  If you have (better than) fighter pilot eyes, then you will see it.

Kinda like a high-priced sniper rifle.  If you have the ability to squeeze the accuracy out of it, then it's worth it.  If not, then you're wasting your money (as far as mission capability is concerned; if you just want it, drive on).

I suppose that's partly true, but what norbs said is aswell.

If it suits your needs then yeah that's all that's needed, but even subtle quality differences that you don't directly perceive will have an effect. There's much that's processed away from what we consciously perceive but that doesn't mean it doesn't make a difference.

But I agree, for practical, hunting for example, purposes, I think it doesn't matter.

Well, last night I managed to see a difference in specs. Sort of.

I have dual Omni v7 gen 3 pvs-14’s.

Up until last night both tubes looked identical to me. Last night I was in my bedroom and it was almost pitch black. Only two light sources are two LED’s from chargers. Both 14’s looked the same.

Then I went into my walk in closet which was even darker. When I closed my right eye I could barely make stuff out. But I could. When I closed my left eye I couldn’t see anything.

So not that I doubted anyone but it appears specs really come into play when you’re facing total darkness or almost total darkness. I wish I knew the specs of my tubes but I don’t. I just know they are Omni 7 gen 3 autogated.

Does the one that lost image sooner perhaps have a slight "glow" when totally light starved, more pronounced than the other?

EBI is probably the easiest to spot, and now speaking with very limited experience here, as at some point it may obscure something another tube still sees.

Murtis beat me to it. Would wager that the tube that lost the image first has a higher EBI. Also can be described as a more "milky" appearance where the black portions of the scene appear more subdued and more "gray" when light levels are very very low.

Would pick a lower EBI tube over a better SNR tube any day. Performing a side by side test with a very low EBI tube that has a lower SNR and a tube with a better SNR but average at best EBI is a very eye opening experience. The image fades out into a milky glowing mush with the average EBI tube while the very low EBI tube still forms an image, though noisy. At these very low light levels, image noise is far less of an issue and far less distracting as there's still a signal for the brain to interpret whereas with a higher EBI tube, that signal blends into the milky glow first and vanishes altogether.

I will second txdx about diminishing returns when specs cross a threshold that even those with perfect eyes wont be able to discern past a certain point. Also i will bet that the Army and Navy have known about this for some time now. as evidence I would say to take what you know as the rumored reason that the minimum requirements for tube specs were lowered slightly from Omni-7 to Omni-8.  most take the rumored reason that ITT was having trouble keeping up with production  and was falling behind on contract fullfilments. Maybe that could be why the specs were lowered, but I would not bet money on it as being the actual reason for the drop in spec requirements. I would not think that iTT, who gets 80% of military tube contracts and can produce their tubes at a cheaper cost due to the costs they saved by simplifying the power supplies by integrating the PSU and outer tube body into one piece and streamlined their production lines, had any issue keeping up with omni-7 contract fulfillment while meeting specs requirements. This is evidenced by the fact that everyone and their mother has an ITT omni -7 era pinnacle tube, and omni -7 era pinnacles are the tube I see more than any other tube. And plenty of the 7 era tubes im talking about are commercial spec'd tubes also. So it would suggest that Itt had no issue pumping out tubes of all formats it seems for both military and gov't contracts as well as commercially sold tubes. Plus exportable FOM tubes that were being produced for foreign milotary contracts. and on top of that they had recently aquired KM electronics co. That was beforehand a seperate entity that produced power supplies for Itt and others. After aquiring KM, ITT was producing power supplies for their own tubes and still selling power supplies to L-3 so L-3 could fulfill the other 20% of the militaryand gov't contracts they were falling behind on. ITT has never been one to fall behind in production. so after thinking about it on that perspective,, it then makes you wonder why then did the minimums drop for Omni-8? The only reason I can come up with that makes any real sense is that the army and navy found out through research, testing, experimenting as well as analyzing feedback from many many Soldiers, Marines and Sailors and any other ways to source the data they were searching for, that omni 7 minimums were either over or at the point at which specs will no longer have huge observable differences to  the vast majority of users of the equipment. there may be a select few who can see a difference at slightlynhigheer specsd than others, but not many and they will have close to perfect vision. I doubt you will ever again see a raise in the minimum spec requirements for omni tubes. Which wouldnt make sense if the spec requirements were only lowered because ITT was falling behind in tube production. Once tube production was back to normal I would suspect the minimums would ve heightened as well. It wouldnt make sense to keep them at the lowered minimums forever. Anyways just my theoryI came up with from the knowledge and experience I have with tubes and the knowledge of ITT and Litton/L-3 historical data. I vcould be mistaken in my theory, but id bet this is the reason for the drop in minimums before I ever put money on the idea that ITT couldnt keep up with demand at that time.

Hmmmm, maybe. The reason I say maybe is I might be seeing exactly what you’re describing but I’d call it more of just....uh....man, yeah. Maybe it’s a glow. It’s almost as if the image goes ghost. Now that you’re pinning me down it’s sirta difficult to explain. I doubt it’ll work but I’ll try to snag pics.

Yes, specs matter very much, but understanding them is the complicated bit.

However, from a simple perspective, things have been pretty good since Omni IV and if you took an Omni IV and a 40S/N Filmless out with the same lenses and tested them side by side, you probably wouldn't notice any difference.

Until about NL6 and when using them indoors with limited light coming through windows at night. To test, take both into a dark room, at night, and take some black duct tape. Start taping up door cracks and curtin openings until the newer higher S/N tube can just make out an image without IR, then test the older tube beside to understand the difference.

Under these circumstances, the S/N verges quite a bit, and the newer tube will still provide an image while the older tubes will indeed struggle.

However, because these tubes automatically compensate above a set level, and most use occurs in natural illumination above this level, there's not much difference between tubes.

In the case of military use, this can make a lot of difference. For civilian use? Not so much.

What is really needed however, especially for civilian use, is a way of testing the tubes so you know whether or not it's still performing as you need it to.

Regards
David.

Could be EBI very well. If you look carefully, you can see it in starlight conditions too where the lower EBI tube has darker darks like txdx described. Look at a tree with at least some foliage/reflective material behind it and the one with higher EBI should show the dark tree trunk a bit lighter in brightness. It looks to me like lower EBI comes with more contrast as the blacks are deeper. Currently I run two tubes with clearly different EBI in a bino and in higher light the one with higher EBI is more pleasant, but when it gets very very dark the lower EBI tube pulls ahead while the other "ghosts out"

If you try take a pic of it, I suppose you'll need a rather long exposure to bring out the differences.

This is really fascinating.  Especially looking at theoretical vs actual performance.  Interesting turn of the thread.

At one point, I was just thrilled to get NV, any NV.  When you don't have anything, and then you have a device, it's a hug leap forward.  As you discover the subtle differences between units, you naturally find yourself wanting to upgrade your capability.

With Murtis' excellent post, you now have to take a look at not only specs, but which spec might be more important to you.

At the one end of this discussion, you have a legit war fighter, with 20/10 vision, who can leverage the best specs to the max extent possible.  On the other end, you have analysis which suggests that specs may have been lowered due to the average user not being able to discern the difference.

I would add that attending some of the classes that are available, where folks like TNVC have product available for testing, might give you an indication of what you can see with it.  If you can combine that with what actual scenarios you might find yourself in, then you should have a pretty clear picture of what you could use.  For example, if you live in a suburban area, with mixed light conditions.  And your vision is 20/20 uncorrected.  You try various spec'd tubes and see if you notice any difference in realistic training exercises.

I would think this is the only real way you are goin to know for sure if the specs matter, to you.

Great thread.

Ok. I tried to take pics last night but the light coming from the screen of my phone totally ruined the darkness. I’ll have to figure out a way to tape off my screen.

But looking again yes, it’s almost like a glow.

On a side note these things really do impress. Like I said I have two leds in my room and they aren’t big. So my room is dark. My walk in closet is even more dark.  As close as makes no difference to pitch black. And I still have to go to the farthest, darkest corner AND close my bedroom door to keep the small amount of light from the living room out before The image goes bye bye.

Yes. That a good way to describe it.

There isn’t a huge difference but it’s definitely there. There is definitely a point where one tube is still (barely) useable and the other is not. Again, mind you, in as close to pitch black as it can get.

That’s an excellent thought David. The worrier in me was wondering if I was wearing my tubes out (lol, I know) but after realizing I can still make out items in just about pitch black probably means my tubes are still tip top.

No doubt it's hard to capture it.

I had to go again and try it myself too and without a proper camera mount I had no luck. My environment was otherwise 100% light proof, except there was a fluorescent bulb that was turned off the while I waited for my eyes to dark adapt (20min perhaps). Was not visible with dark adapted eyes, but the slightest glow was through NODs. Before the higher SNR, higher EBI tube lost the image only things that were visible were those squiggly worms going around the tubes and behind those worms the low EBI tube showed a faint image.

Then walked into the sauna that had only got the 20min old afterglow of the fluorescent bulb via a few walls and some meters, and to my surprise there was still something visible, although I could make no sense of it. But when I turned my head I noticed the nice display of worms is moving along the scene, but if I didn't know what was where I could not have said I actually saw anything. Never checked them in this dark with dark adapted eyes and noticed this.

Yeah that's an interesting phenomena.  I have noticed a kind of "afterglow" from some of my florescent lights, especially after my eyes have become adapted to low light.  There is a noticeable glow from them, way after you turn them off.  Even more so with NV I'd suspect.

Very interesting stuff on the EBI.

But again I would ask the question, is this just academic discussion about what they can do, or is it tied into your specific use?  Really good low light performance may or may not be applicable to you and your situation.  For instance, do you live out in a rural area, with little artificial light, or do you live in a suburban area with lots of different light, practically 24/7?

In my opinion, if you ask the question if specs really matter, it can't be answered in a vacuum.  Matter to who, and what situation. If the OP is posing the question to the civilian audience, then is he talking about night hunters, or what?  If you are talking about mil-spec use, then again, take your pick of scenarios.

I do this myself, so it applies to me as well, but we talk about going in our closets and trying things out and then basing our requirements on this stuff.  Or we wonder around in our back yards and see what we might, and then think we're GTG.  I think we are kidding ourselves if we think that this gives anything but a bare inkling of what we really might require.

So really, while this all is very fascinating, what we really need to do, in order to answer the OP, is to go out into typical areas we might be operating NV, to whatever end, and see how it really performs.  Especially if your buddies have different kit and you can compare it side by side.

It seems sometimes there is this undertone here, that NV is somehow the magic ju ju, that once you have it, you are like some super hero and are invincible.  So if you increase the capability of your NV you are increasing your superpower.  I think that, in reality, NV is a great enhancement of one sense, but if you do not posses the rest of the skill sets required for your mission, whatever that may be, then you may fail regardless of how spiffy your NV is.  So the larger question is do NV specs matter, outside the laboratory (or closet) as much as we think they do?  Outside of the obvious, of obtaining the best equipment available/affordable for your mission, the outcome is really dependent on your performance, on the day, with what you have.

So the answer is a definate maybe.

Yeah, without a doubt I don’t “need” a top spec tube. My typical AO is in the middle of the desert and even on moonless, starless nights I’ve never had an issue seeing what I needed to, which is paper targets and metal gongs. Lol.

I mean yeah, I'm not an assaulter for JSOC, so I don't "need" state of the art equipment either.  Not that I wouldn't love to have it.  But then how much of that would be hobby, and how much actual requirement.  That is my yard stick.  As always YMMV.  So I'm not banging on anyone here; if I could afford it, I would get the best TNVC has to offer, just cuz.

But when you ask the question "how much do specs matter", well...

Well said. I have not seen a modern L3 high spec tube, so I really don't know what the difference is to sub 30 SNR tubes, but I would still say specs don't matter that much for the common guy. Most Omni IV and onwards or Gen2+ Photonis >20SNR will suffice in 90% of the situations. After a certain range depending on mag you will need supplemental IR anyway so the passive thing flies out of the window. Also, I would go and say 90% of the time specs are mostly just cosmetics, until you really need something specific. Things like optical axis offset / fiber irregularities & output brightness are specs that really do matter in a bino, but that's another thing then.

Range gated NV is interesting although I have not used one. What I hate about regular supplemental IR is the backsplash from tree branches, bushes, whatever, that totally obscures anything you're trying to see better. For any use that is not strictly passive due to the nature of the work range gating would make many spec talk go away as you'd be able to see through stuff in occluded forests where you'd normally see nothing if it's dark enough - with or without extra illum.

Here's an old thread about those, specifically the one that Katod makes: Range gated NV (Katod)

Slightly sorry for derailing the OP question more, but as with the EBI having effect on very low light performance and bringing more contrast, range gating is very interesting and something I could see myself using. The Katod unit uses a Gen2+ tube and it really doesn't need a Gen3 as you have that extra super power to see "through" stuff.

Range gating seems like a cool solution but the illuminator would have to be tied to the autogating.

These threads are awesome and make me wish my tubes were higher spec.

Just got some L3 filmless white phos tubes with a 29.x snr and 72lpmm. They work great but you always hope for better specs especially since they are brand new and everyone else seems to have a norm of 33-34 snr.

I have been comparing them to my older omni 7 with 27 snr and 64 lpmm and plan to test them as you all have so I can hopefully see the difference in ebi.

Yes indeed, fascinating stuff here.  Thanks to Murtis and others who have shared their knowledge here.  I had no clue about this stuff until reading about it here.  Things like EBI, and range gated.  I have never found another open source that really explains all this.  Knowing some of these things, you could really tailor a device to your specific requirements, be it extreme low light conditions, or "seeing" through thick woodlands.  Or both.

So in that sense, yes, specs do matter; however, as Murtis said, for the average bear, it probably isn't really necessary.  If NV is part of a budget for a particular mission, be that hunting, or self defense, then it has to be seen as part of an overall package.  From that perspective it is a huge chunk of the budget, where many other things must be purchased first.  But if NV is the mission, then yeah, you can blow the whole budget on it.  For sure and why not.

This is arfcom.  Some guys are here to show off their state of the art gear.  Which probably sits in a safe all the time.  Some guys are real Jeagers, hunters at night.  Some guys are into military arts, for various reasons.  And yes, some guys are real warriors.  It's like a Polish parliament; getting any consensus on something is a rare occurrence.