School me on nightvision

[Nocaster]

...and up, start getting into 2400+ FOM with solid well rounded specs you can add another grand to that.


Absolutely, learn what the numbers mean and how they are applied...most folk will just look for a FOM monster but I'd give up a some FOM for better (lower) EBI and HALO numbers.

Also, especially for older eyes, SNR is way more important than Resolution, and FOM is the snr number multiplied by Resoluton

 

[titsonritz]

Oh I was looking to buy one quess I should be more specific

I figured that, which is why I pointed out that dude's ad, it is a good price. On the flip side, if you are running a bump or ballistic helmet take a look at the Norotos INVG, it is probably the best dedicated PVS-14 mount out there. I went with the Wilcox setup because I using a Crye Nightcap and didn't to deal with a force-to-overcome type mount.

 

[titsonritz]

Also, especially for older eyes, SNR is way more important than Resolution, and FOM is the snr number multiplied by Resoluton

Yep, that linked article gets into it pretty good. Here is that part...

FOM is a calculated number using resolution (res) multiplied by the signal-to-noise ratio (SNR). FOM = Res x SNR. It's probably the most used for how good a tube is. It isn't the be all end all but it's a damn reliable way to determine a tube's general performance / quality.

HOWEVER......the center resolution affects the FOM number significantly so it is possible to get a high FOM tube that sucks compared to one with a lower FOM. As an example, a 2200 FOM tube with 81 center resolution means it has a SNR of 27.16. That SNR is pretty average. Now take 2200 FOM with a 64 center resolution and you have 34.38 SNR! The difference in performance between these two tubes (all other specs being similar) will be very noticeable even to the novice.

The majority of newer gen 3 tubes will have a minimum center resolution of 64 lp/mm (line pairs per millimeter) however 72 is common in L3Harris unfilmed WP and 81 is becoming more common with Elbit thin filmed WP. I'm not a fan of 81 RES tubes when it comes to your typical head mounted night vision device.

Previously, I ranked FOM numbers based on 64 RES. My new ranking of gen 3 FOM is based on 72 RES as the maximum. 2376+ is the new "gold standard" in my opinion using 72 RES as the maximum. Why 72, you might ask? Well, do the math and whether it's 64 or 72 RES, at 2376+ you are 100% guaranteed a high SNR number. 81 RES is pretty much BS when it comes to FOM because it is an easy way to fluff the FOM number, and IMO is very likely being used for that exact purpose. Perfect example, you would need a 2800 FOM 81 RES tube to get the same SNR as a 2376 FOM 72 RES tube. If you're shopping for high FOM tubes then you need to ask what the Resolution is.