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10/30/2020 2:42:12 PM
Posted: 11/17/2020 10:11:33 AM EST
[Last Edit: 11/17/2020 10:11:49 AM EST by tunatuk]
A buddy and I were just talking, and he came across one of these:

https://www.sureshotnightvision.com/snb-filters/

I'm of the opinion that garbage in = garbage out, so I don't think that it can amplify anything anymore than it already is, nor can it clear something up that isn't clear to begin with.  I'm new to NV, but it seems like a gimmick to me.  It seems like its trying to do a CSI enhancement on a photograph that was seen in a mirror that was reflected off of someone's eyeglasses from 300 feet away, and still being able to read the license plate clearly.

And while I've got your attention, can someone explain amber filters to me? Do they do anything to help with eye strain, or what is their purpose?
Link Posted: 11/17/2020 10:14:11 AM EST
What in the Billy Mays as seen on tv is this...
Link Posted: 11/17/2020 10:25:48 AM EST
I've found them to work as advertised, reducing the snow effect a fair amount. At the same time though, they do noticeably cut total light output, so if your eyes aren't more dark-adjusted the tubes will be less effective than if unfiltered and at max gain. This is more pronounced if you're just picked up your NODs for a quick look or comparison test on/off. If you take the time to use them for a bit, your eyes adjust and the effect seems pretty decent. They haven't appeared to have other negative effects on image quality like reduced sharpness. Just less snow and a bit less brightness (and purple tint).

I've also tried them recently sized/cut/mounted for clip-ons (re-tubed 27s) and found a similar experience. Clip-ons to me are typically quite a bit darker than head-mounted units though, so it more noticeably affects usability at a quick look.

I don't own any of the filters, have just borrowed them from folks to give them a try and my thoughts in the past.
Link Posted: 11/17/2020 10:27:36 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By tlandoe07:
What in the Billy Mays as seen on tv is this...
View Quote
That tells me what I need to know right there...

Any thoughts on the amber filters? Or is that something that Billy's buddy Anthony Sullivan is selling on the next channel?
Link Posted: 11/17/2020 10:34:32 AM EST
Link Posted: 11/17/2020 11:08:27 AM EST
These appear marketed to reduce the noise, which isn't possible. Even in the grainy cell phone photos you can still see the scintillation. It's just more muted because it has a purple filter on it- if you notice, everything else is muted too.

This is because it's a filter. Filters work by color subtraction. LIFs and ANVIS lenses reduce certain light wavelengths (LIFs being green, ANVIS being Red/Amber/Green). Simply put, the color of the filter is the color of the light that it will allow through. White light consists of red, blue, and green. A green filter will allow green light to pass, and it will absorb (block) red and blue. The same is true of the other colors in relation to one another.

This filter appears to be a variation of light magenta, which would block 50% of green light and pass 100% of red and blue (magenta being a mix of red and blue). The spectral range of a P43 image tube is about 525-575nm. P45 are about 400-450nm.

Simply put, you'll theoretically lose about 50% of your performance if you run green phosphor. And if you're running white phosphor, you have a high enough SNR that this would be irrelevant to begin with.
Link Posted: 11/17/2020 11:46:46 AM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By tlandoe07:
These appear marketed to reduce the noise, which isn't possible.
...
This filter appears to be a variation of light magenta, which would block 50% of green light and pass 100% of red and blue (magenta being a mix of red and blue).
...
Simply put, you'll theoretically lose about 50% of your performance if you run green phosphor. And if you're running white phosphor, you have a high enough SNR that this would be irrelevant to begin with.
View Quote

In my hands-on experience, I'd disagree. And I think your assumptions on the makeup of the filter intensities are likely wrong. Also, I found them to achieve their stated goal quite well on white phosphor tubes, maybe more-so than green ones.
Link Posted: 11/17/2020 11:50:25 AM EST
I've never tried the SNB filters because my unfilmed WP tubes reside mainly in an Anvis goggle which like mentioned above is already "filtered".

I have used high quality glass amber filters with my GP PVS-14s. It does increase contrast and cleans up the static some but at the expense of lowering the brightness. I'm sure the purple filters perform the same way. I'm not a huge fan of them but they have their place. It's like anything. Some guys love it and have a solid use case while others don't.

The benefit I've personally experienced from the amber filter, is since I'm using 10160 tubes in my -14s I don't have a way to lower gain, and on brighter nights the filter functions to lower the brightness. So with that in mind, I'm sure they are an option for someone with a set of WP goggles with 10160 tubes who wants a way to lower brightness.

It makes sense to use a filter to lower the brightness on thermal displays. That blue blocker thread a ways back actually isn't a bad idea IMO.
Link Posted: 11/17/2020 12:02:46 PM EST
[Last Edit: 11/17/2020 12:12:16 PM EST by tlandoe07]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By jwramp:

In my hands-on experience, I'd disagree. And I think your assumptions on the makeup of the filter intensities are likely wrong. Also, I found them to achieve their stated goal quite well on white phosphor tubes, maybe more-so than green ones.
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You’re free to disagree all you want, they’re filters which limit light transmission of a given wavelength. That is a fact. They don’t reduce noise, they reduce the entire pass through of light to the eyes since they’re on the ocular side of the unit. The only way to reduce noise would be to get a better tube where noise is not as much of a limiting factor to performance.

I’m not surprised they work better on white though, since they would not be filtering the wavelengths of white as much as they would of green.

ETA: the perceived reduction to the video noise is directly proportional to the total reduction in light passed through the filter.
Link Posted: 11/17/2020 12:10:35 PM EST
I got to use some Saturday night at the snipershide shoot. The ones I tried were on green tubed goggles. I didn't notice any gain loss, so if there was some, it was a lot less than a Wilcox amber filter and less than putting a LIF on the ocular.

The image did appear a little less green, almost a green/white mix. The guy who let me try the goggles had just bought them at the shoot after trying them out. I think they seemed useful and may pick some up down the road.

Tlandoe's assessment of 50% loss must be a gross exaggeration, but I'm not putting a soldering iron to them...
Link Posted: 11/17/2020 12:15:41 PM EST
Originally Posted By tunatuk:

And while I've got your attention, can someone explain amber filters to me? Do they do anything to help with eye strain, or what is their purpose?
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@tunatuk
I didn't answer you directly in my other reply.

The original intention was to reduce the green splash back from the eyepiece on the users eyes/face for stealth reasons. AFAIK, the Wilcox was the original and it accomplished the task but at a huge expense of lowered performance. It's a much darker color compared to the newer glass amber filters.

The glass amber filters being sold now accomplish reduced eye splash to a certain degree but the main benefit is increased contrast and reduced brightness with green phosphor tubes. Amber also works well in combination with head mounted thermal with the thermal palette on Sepia in the case of the FLIR Breach.
Link Posted: 11/17/2020 12:15:59 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By SGT-Fish:
I got to use some Saturday night at the snipershide shoot. The ones I tried were on green tubed goggles. I didn't notice any gain loss, so if there was some, it was a lot less than a Wilcox amber filter and less than putting a LIF on the ocular.

The image did appear a little less green, almost a green/white mix. The guy who let me try the goggles had just bought them at the shoot after trying them out. I think they seemed useful and may pick some up down the road.

Tlandoe's assessment of 50% loss must be a gross exaggeration, but I'm not putting a soldering iron to them...
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It’s not an assessment, it’s an estimate based on data of what the extreme fringe of light transmission reduction could potentially be.
Link Posted: 11/17/2020 1:45:35 PM EST
[Last Edit: 11/17/2020 1:46:22 PM EST by great308]
It’s not so much a snr booster as it is a scintillation reducer. You can’t boost SNR by filtering. You can however reduce the scintillation by filtering. Simple terms as I understand it and correct me if I’m wrong, scintillation is a by product or effect of the tube trying to produce a image in low light.

Higher snr means you should be able to make out an image in low light better than you would on low snr. This filter is just taking away some of the scintillation and not actually boosting the snr, in fact it might actually be lowering the snr but that is just a guess.

This last part I’m just theorizing, maybe the filter is tricking the brain a bit to think you can pick out a image better with the filter. When you have scintillation it causes the image to be busy and your brain can kind of get distracted by it. So is it actually doing anything better or is it just taking some of the busy away so the brain can focus on what is there already?
Link Posted: 11/17/2020 2:03:31 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By great308:
It’s not so much a snr booster as it is a scintillation reducer. You can’t boost SNR by filtering. You can however reduce the scintillation by filtering. Simple terms as I understand it and correct me if I’m wrong, scintillation is a by product or effect of the tube trying to produce a image in low light.

Higher snr means you should be able to make out an image in low light better than you would on low snr. This filter is just taking away some of the scintillation and not actually boosting the snr, in fact it might actually be lowering the snr but that is just a guess.

This last part I’m just theorizing, maybe the filter is tricking the brain a bit to think you can pick out a image better with the filter. When you have scintillation it causes the image to be busy and your brain can kind of get distracted by it. So is it actually doing anything better or is it just taking some of the busy away so the brain can focus on what is there already?
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You’re basically correct. Filters block certain light and allow certain light to pass. Image tubes are monochromatic, so they only display in black and whatever the phosphor color is. So, no matter what you are reducing perceived noise at the cost of overall output brightness (gain) and as such you can expect generally lower performance in areas such as low light resolution, resolution at distance, focal precision, etc.

You might perceive a decrease to noise but that’s because the scintillation is being blocked by the filter- and that means signal is being blocked as well. As to what percentage, that depends on the composition of the filter. A 50/50 magenta filter (50% blue, 50% red) will filter 100% of green light. A light magenta filter (25% red, 25% blue, 50% transparent) filters 50% of green. Color filtration is pretty simple to calculate, I imagine that whoever created this did their homework to arrive at a specific filter design that achieves the desired outcome. But that doesn’t change how filters work, and how they work results in a net decrease to light transmission.

I don’t have any issue with people running filters, useless as I think they are, but I presume this really would only apply to low SNR tubes anyway in which case you’d be making a lower performing tube worse.
Link Posted: 11/17/2020 2:55:35 PM EST
[Last Edit: 11/17/2020 2:56:39 PM EST by FoxValleyTacDriver]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By tlandoe07:
What in the Billy Mays as seen on tv is this...
View Quote


Look, if it reduces light transmission, it does technically reduce the scintillation and noise reaching your eye
Link Posted: 11/17/2020 4:38:25 PM EST
[Last Edit: 11/17/2020 4:40:35 PM EST by texassooner]
I dont know about a snr booster....but they do a pretty good job reducing scintillation.  They work particularly well in higher light scenarios when the moon is out, etc.  I use one on my Iray 100% of the time to reduce eye strain.
Link Posted: 11/17/2020 4:57:31 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By tlandoe07:
These appear marketed to reduce the noise, which isn't possible. Even in the grainy cell phone photos you can still see the scintillation. It's just more muted because it has a purple filter on it- if you notice, everything else is muted too.

This is because it's a filter. Filters work by color subtraction. LIFs and ANVIS lenses reduce certain light wavelengths (LIFs being green, ANVIS being Red/Amber/Green). Simply put, the color of the filter is the color of the light that it will allow through. White light consists of red, blue, and green. A green filter will allow green light to pass, and it will absorb (block) red and blue. The same is true of the other colors in relation to one another.

This filter appears to be a variation of light magenta, which would block 50% of green light and pass 100% of red and blue (magenta being a mix of red and blue). The spectral range of a P43 image tube is about 525-575nm. P45 are about 400-450nm.

Simply put, you'll theoretically lose about 50% of your performance if you run green phosphor. And if you're running white phosphor, you have a high enough SNR that this would be irrelevant to begin with.
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In theory.....but not in reality..... I’ve spoken to jay about these filters in depth and without giving away his intellectual property and how he developed the lens I can tell you that there is some thought and testing behind it. It works as advertised and does not cut tube performance by 50%.  Don’t knock it until you try it.
Link Posted: 11/17/2020 5:06:37 PM EST
Link Posted: 11/17/2020 5:14:49 PM EST
Link Posted: 11/17/2020 5:33:35 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By texassooner:



In theory.....but not in reality..... I’ve spoken to jay about these filters in depth and without giving away his intellectual property and how he developed the lens I can tell you that there is some thought and testing behind it. It works as advertised and does not cut tube performance by 50%.  Don’t knock it until you try it.
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I’m sure the proprietary secret sauce is super reality-defying. I’ll just stick to tubes with higher than a 24 SNR. Ymmv
Link Posted: 11/17/2020 5:40:11 PM EST
I don't like em, I have a buddy that does. I'll say they reduce the brightness much more than Anvis glass.

They're plastic to so they scratch easily.
Link Posted: 11/17/2020 6:11:38 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By ARShooter91:
I don't like em, I have a buddy that does. I'll say they reduce the brightness much more than Anvis glass.

They're plastic to so they scratch easily.
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Good info. I assumed they were glass at $80 a pop.
Link Posted: 11/17/2020 7:04:49 PM EST
Originally Posted By tunatuk:
A buddy and I were just talking, and he came across one of these:

https://www.sureshotnightvision.com/snb-filters/

I'm of the opinion that garbage in = garbage out, so I don't think that it can amplify anything anymore than it already is, nor can it clear something up that isn't clear to begin with.  I'm new to NV, but it seems like a gimmick to me.  It seems like its trying to do a CSI enhancement on a photograph that was seen in a mirror that was reflected off of someone's eyeglasses from 300 feet away, and still being able to read the license plate clearly.

And while I've got your attention, can someone explain amber filters to me? Do they do anything to help with eye strain, or what is their purpose?
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Signal to noise is the amount of light falling on the photo cathode divided by the amount of noise generated inside the tube. A filter on the input to the tube will make the S/N worse. A filter on the ocular end does nothing to S/N but may play some game with the eye and trick it into thinking the S/N is better but I would be very skeptical. I am old enough to remember people selling filters that converted black and white TV's to color, it was a peace of rainbow colored plastic you put in front of your TV. Yep, we had color TV.
Link Posted: 11/17/2020 7:15:23 PM EST
I have a set. While they don’t exactly boost S/N, they do clean up some of the “fuzz”. The flip side of that is they are a filter and as with any filter, they degrade performance as seen by your eye. So essentially making the problem you were trying to fix worse. The purple color over WP tubes looks cool as shit though
Link Posted: 11/17/2020 7:24:24 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By TNVC_Sam:
Lets all be real clear, you aren't boosting anything with these. Its filtering photons, not increasing photons on the Photocathode or increasing voltage on the MCP.

If they work they work, but the name of the product is slightly misleading.
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Fair to say. But saying they cut half the light out is disingenuous as well.

For anyone interested, they can be had for under 80 bucks.
Link Posted: 11/17/2020 7:50:50 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By tlandoe07:


It’s not an assessment, it’s an estimate based on data of what the extreme fringe of light transmission reduction could potentially be.
View Quote View All Quotes
View All Quotes
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By tlandoe07:


It’s not an assessment, it’s an estimate based on data of what the extreme fringe of light transmission reduction could potentially be.




Originally Posted By SGT-Fish:


Fair to say. But saying they cut half the light out is disingenuous as well.

For anyone interested, they can be had for under 80 bucks.



If you took a moment to actually read the thread...
Link Posted: 11/17/2020 7:51:19 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By SGT-Fish:


Fair to say. But saying they cut half the light out is disingenuous as well.

For anyone interested, they can be had for under 80 bucks.
View Quote

Yeah not nearly that much. Seems to be on par with most amber filters as far as I can tell
Link Posted: 11/17/2020 8:08:26 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By tlandoe07:
If you took a moment to actually read the thread...
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I did. And jumping to extremes when you havent even handled the product is well, extreme...
Link Posted: 11/17/2020 8:25:22 PM EST
Two or so years ago I fooled around with input and output filtering of PVS-14 for other reasons than this product claims.

I bought filter sample sets from Roscolux. Got a 2" thick stack of different colored flexible plastic filters for a just few bucks. The smallest sample sheets (perhaps 1" by 2") can easily provide two eyepiece or objective lens filters.
Never found any filter that, used on either end of a PVS-14, did anything at all that I thought was an improvement of any kind. I admit that disguising SNR never entered my mind and I wouldn't have assumed the actual SNR was one bit better even if it had seemed so, especially when conditioning only the exit end of the tube, because, in my opinion and based upon experience with SNR in other fields, the notion is preposterous.

Might result in a view that is more pleasing to the eye though, and if it is, the color of the product looks very close to the color of the tinted safety glasses sold to help gardeners see damaged or stressed plants. Those might be worth a try.
Link Posted: 11/17/2020 8:26:56 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By SGT-Fish:



I did. And jumping to extremes when you havent even handled the product is well, extreme...
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Explaining how filters work isn’t jumping to an extreme.

Trying to justify a product that objectively limits performance as actually enhancing performance is extreme. But you do you booboo. Spend your money on whatever you want, if there was a significant performance gain demonstrated by putting a filter on the eyepiece, everyone would be doing that instead of waiting in line for high performance image intensifiers.

I can’t speak to your level of experience, or your sample size of night vision units you’ve used, owned or built, but I can definitely rely on mine.
Link Posted: 11/17/2020 8:27:22 PM EST
Kind of want to try but im too cheap for that
Link Posted: 11/17/2020 8:49:58 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By rlltd42:
Kind of want to try but im too cheap for that
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You’re a old timer here with lots of feedback. I’m not using mine if you want to check them out
Link Posted: 11/17/2020 11:44:40 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By tlandoe07:


I’m sure the proprietary secret sauce is super reality-defying. I’ll just stick to tubes with higher than a 24 SNR. Ymmv
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You should dust off your soldering iron and show us a thing or two about what you know.  I’ll stick to my personal experiences and not conjecture from a Facebook night vision dealer that hasn’t even handled the product he’s bashing.  YMMV.
Link Posted: 11/18/2020 6:42:12 AM EST
[Last Edit: 11/18/2020 7:31:12 AM EST by tlandoe07]
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By texassooner:



You should dust off your soldering iron and show us a thing or two about what you know.  I’ll stick to my personal experiences and not conjecture from a Facebook night vision dealer that hasn’t even handled the product he’s bashing.  YMMV.
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The emotional investment into equipment is strong with you, I see. I never bashed a product, I explained the theory behind how it worked (and how it does not work). And pointing out that all these are are filters that reduce light transmission is a statement of fact. If that hurts your feelings for some reason, that’s unfortunate.

Link Posted: 11/18/2020 7:42:20 AM EST
iF yOu AcTuAlLy rEaD tHe ThReAd

You'll see that not a single person denied that they reduce light transmission. But we are talking about the benefits and consequences of such light FILTERS.



The amount of emotional investment in a product that you have zero experience with is telling...
Link Posted: 11/18/2020 8:28:59 AM EST
[Last Edit: 11/18/2020 8:29:13 AM EST by TNVC_Sam]
Link Posted: 11/18/2020 8:37:53 PM EST
Most if not all filters will degrade performance to a certain degree. That applies to filters of the same type too. For example amber filters can be very different between manufacturers. Orion filters are a light yellow, Wilcox are a medium Amber, and ACT filters are a dark amber, and they all perform differently. Ultimately how much you lose vs what you gain in return should be the deciding factor if that filter is actually worth using, IF we are being objective. I used the SNR booster type a few times and while it was interesting, I didn’t really see I was gaining anything
Link Posted: 11/18/2020 10:39:27 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By DevilWillCry:
I used the SNR booster type a few times and while it was interesting, I didn’t really see I was gaining anything
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I don't think it is possible to affect SNR except by improving the size and quality of the objective lens to maximize the view of the particular object being observed and do that while providing the optimal amount of illumination through to the tube while the gain control is set at the best possible position to minimize the intrinsic noise floor of the tube. Everything behind that tube gain stage is going to (or fail to)  illuminate the phosphor with the signal and the noise and nothing back there can change the ratio. After all, the noise and the signal will excite the phosphor in identical ways and result in identical phosphor responses. Except that noise will be randomized about the field (generally) while the scene tends to remain far more uniform and static.
Having said that, perhaps it is possible to pass from the phosphor only wavelengths that stimulate the slowest of vision receptors and thereby "eliminate" sudden flashes of noise or scintillation, but if that is the case I'd opt to keep my whole visual capability in the game anyway.
But that's just my opinion.
What do I know?
Link Posted: 11/19/2020 1:31:18 AM EST
A friend of mine uses one to tone down FPN for photography. Excellent tube, just got some FPN. Kindof "off label" use I guess.
Link Posted: 11/19/2020 7:02:50 AM EST
I kinda think of it the same way as polarized sunglasses. Not an perfect comparison. With polarized lenses I can see past glare and do things like seeing fish under the surface of water better, while cutting out some light and making it hard to see oncoming aircraft when flying. So its a situation dependent use.

I'm making no claims about the science of these or any other filters. It is obviously that they block some wavelengths of light. Whether or not that improves your vision is up to you. It also obviously does not boost the actual SNR of a tube, though it may boost the perceived SNR.

Like i said before, I may buy some. Especially for when the ground is snow covered and I don't have manual gain
Link Posted: 11/19/2020 9:09:57 AM EST
Well, I was considering it.

But I live in the deep south, and have manual gain on my NV, so I don't see the need for it.  I don't deal with snow, and I almost always have supplemental IR with me when walking around, shooting, hiking etc. so I don't ever have my gain cranked to 11.

The technical discussion did make me think about it differently.  I was aware that filters cut some of the light, but just didn't consider that.  Kind of ironic that the way NV works is by amplifying light, so in order to reduce some of the affects NV has on the image we put a filter after to cut back some of the light we just "magically" amplified using the magic smoke inside our plastic tubes.
Link Posted: 11/19/2020 9:37:28 AM EST
[Last Edit: 11/19/2020 10:01:55 AM EST by tlandoe07]
Originally Posted By SGT-Fish:
iF yOu AcTuAlLy rEaD tHe ThReAd

You'll see that not a single person denied that they reduce light transmission. But we are talking about the benefits and consequences of such light FILTERS.



The amount of emotional investment in a product that you have zero experience with is telling...
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I’ll leave the actual technical discussion up to you experts then and just keep my baseless theories to myself.

Originally Posted By tunatuk:
Well, I was considering it.

But I live in the deep south, and have manual gain on my NV, so I don't see the need for it.  I don't deal with snow, and I almost always have supplemental IR with me when walking around, shooting, hiking etc. so I don't ever have my gain cranked to 11.

The technical discussion did make me think about it differently.  I was aware that filters cut some of the light, but just didn't consider that.  Kind of ironic that the way NV works is by amplifying light, so in order to reduce some of the affects NV has on the image we put a filter after to cut back some of the light we just "magically" amplified using the magic smoke inside our plastic tubes.
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I’m in southwest Louisiana, if you ever wanna test out some different tube, glass, and filter combos just shoot me a PM.

I have pretty much every common flavor and color of tube in both PVS and AVS glass varieties, ranging from 19 SNR to 37 SNR and numerous types of filter setups that could easily be adapted to go on an eyepiece. Might even just buy one of these to try out so I can come back and report without the peasants jeering at my "lack of hands-on experience".

ETA: If I do, I'll throw it on a 126 and actually test the output brightness to see how much it limits gain.
Link Posted: 11/19/2020 6:42:01 PM EST
Discussion ForumsJump to Quoted PostQuote History
Originally Posted By Feeble-Prize:



I don't think it is possible to affect SNR except by improving the size and quality of the objective lens to maximize the view of the particular object being observed and do that while providing the optimal amount of illumination through to the tube while the gain control is set at the best possible position to minimize the intrinsic noise floor of the tube. Everything behind that tube gain stage is going to (or fail to)  illuminate the phosphor with the signal and the noise and nothing back there can change the ratio. After all, the noise and the signal will excite the phosphor in identical ways and result in identical phosphor responses. Except that noise will be randomized about the field (generally) while the scene tends to remain far more uniform and static.
Having said that, perhaps it is possible to pass from the phosphor only wavelengths that stimulate the slowest of vision receptors and thereby "eliminate" sudden flashes of noise or scintillation, but if that is the case I'd opt to keep my whole visual capability in the game anyway.
But that's just my opinion.
What do I know?
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Correct. It doesn’t actually remove snow from your tubes but the filter does a very good job of masking it. Think of it like this, if you add a muzzle break to a rifle, it doesn’t actually make the recoil go away. Instead, it shifts it in directions that make it less noticeable, aka perceived recoil. It’s the same with the SNR filter, it’s tricking you into thinking there is less snow, and visually I does just that, without actually removing anything
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