Buyer's Guide to Night Vision Rifle Scopes

Scoping out the choices

Aside from their green output image, most night vision devices have very little in common. Their differences can be vast, and it helps to know what these differences are before you buy. The three most important things to consider, in terms of judging performance, are sensitivity, signal, and resolution.

Sensitivity-- otherwise known as photoresponse-- is an image tube's ability to detect light. Sensitivity is measured in "A/lm" (microamperes per lumen). Most decent night vision devices don't come with infrared illuminators, which aren't necessary anyway if the device is sensitive enough. Some manufacturers, however, include infrared illuminators in order to attain better performance in very low light.

Signal also plays an important role in a night vision device's performance. A microchannel plate is used to transfer signals from input to output, so a device with good signal capability is similar to a stereo with high-quality sound. The better the signal, the better device.

Resolution is a night vision device's ability to resolve detail in an image. Most good night vision devices contain a high-end phosphor that creates high-contrast images, with the highest resolution. Beware: some manufacturers produce devices with magnified optics that create the illusion of high resolution but have a poor field of view, while other manufacturers produce devices that offer higher magnification as an option, though not because the device actually needs it for better resolution.

Finally, night vision devices are categorized according to "generations" (e.g., Generation I, Generation II, etc.). The higher the generation, the better the device, so make sure to check the generation before you choose.