Night vision binoculars are binoculars which are designed for use in low-light environments, allowing the user of the binoculars to see more clearly. There are a number of night vision devices on the market, all of which are designed to compensate for the comparatively low night vision available to humans. Some of the best models are designed for military use, but it is also possible to purchase civilian versions along with retired military models. Hunting suppliers, military surplus stores, and science stores are often good sources for night vision binoculars.
There are two ways in which night vision binoculars can work. They can either passively intensify the scene viewed through the lenses, or they can actively scan to generate a thermal or infrared image. The earliest night vision binoculars utilized passive technology, with modern versions being more likely to use active technology, since it is much more sophisticated.
In a passive system, the night vision binoculars have a very wide lens opening which is designed to collect as much light as possible. The light passes through a series of intensifying filters before being emitted through a very small aperture, allowing the wearer to essentially see in the dark. Passive systems often have a greenish tint from the lenses used to filter the light. Correcting the green tone could obscure the image, so it is usually left unaltered.
Active systems are designed to seek out infrared signatures, painting a scene for the wearer. Sophisticated active night vision binoculars can provide a very sharp and clear picture, while more simple thermal imaging versions simply display a scene in blotches of color, with bright spots indicating hot points where an animal or warm engine may be present. One disadvantage of this system is that it requires a power source, which can be cumbersome in the field. As an advantage, however, active systems can see through smoke, dust, fog, and other sources of visual disturbance, while passive systems cannot.
Night vision optics are extremely useful in military applications, allowing members of the military to work in dim conditions. They are also useful for civilian hunters, and for wildlife biologists who want to be able to observe wildlife at night without creating a disturbance. The more sophisticated the optics, the better the image quality, and the more expensive the binoculars will be. If possible, it is a good idea to test night vision binoculars before purchase to determine whether or not they will meet the needs of the user.
