Night vision listings are a wall of acronyms: Gen 2+/Gen 3, FOM 1600, P45, autogating, SNR. It's enough to make you close the tab. Here's what those numbers actually mean for what you'll see through the tube, minus the marketing fog.
"Generation" is the starting point, not the whole story
Generation refers to the image-intensifier technology inside. Gen 3 is the current benchmark for serious use: brighter, cleaner and far longer-lived than older Gen 1 and Gen 2 kit you'll find on the market. But here's the catch the cheap sellers won't tell you: "Generation" alone doesn't mean much. Two Generation 2+ or generation 3 tubes can perform worlds apart. That's where the real number comes in.
Figure of Merit (FOM): the number that matters
FOM is the single best at-a-glance measure of tube quality. It combines resolution (how sharp the image is) with signal-to-noise ratio (how clean it is in low light). Higher is better. A tube in the 1600+ range is genuinely capable kit: sharp, low-noise, and a serious performer on a dark night. When you compare devices, compare FOM, not just the generation badge.
White phosphor vs green
That classic green night-vision look is just the phosphor screen colour. Newer white phosphor (P45) tubes render the scene in cool greyscale instead. Most people find white phosphor:
- Easier on the eyes over long sessions: less fatigue
- Better at showing depth and detail your brain is used to reading in greyscale
- More natural-feeling, especially for first-time users
Green still works perfectly well, but if you've got the choice, white phosphor is the nicer experience.
The supporting cast
- Autogating: the tube rapidly protects itself against sudden bright light (a passing car, a torch), keeping the image usable. Worth having.
- Gain control: lets you dial brightness up or down to suit conditions.
- Resolution (lp/mm): sharpness, already baked into FOM, but you'll see it quoted.
So what should you actually look for?
For most buyers: a Gen 2+ tube, FOM 1600 or higher, white phosphor, with autogating and manual gain. That's a device that will genuinely deliver on a dark night and last for years. Beyond that you're paying for marginal gains: real, but with diminishing returns.
Want a hand matching specs to your use case? Talk to us; we'd rather sell you the right unit than the dearest one.