Night scene viewed by an infrared camera
Surveillance cameras come in many kinds, but two that get attention are the low-light and infrared (IR) varieties. An IR camera detects the heat from people and hot objects like car engines. A low-light camera can take pictures by starlight or other faint sources.
Descriptions
An IR camera is sensitive to invisible light at wavelengths longer than 750 nanometers. It can see anything that's warmer than the background environment. A low-light camera amplifies small amounts of available visible light to produce a useful image out of murky darkness.
No Light
A low-light camera needs at least some visible light to create an image. IR cameras depend on the infrared given off by warm objects only. They can image people even in total darkness.
Ambient Heat
An IR camera needs to see differences in temperature, so a warm environment will blur out warm objects and people. A low-light camera will be relatively unaffected by ambient heat.
Sensitivity
Normal room lighting will overload a low-light camera although it functions well in nighttime conditions. An IR camera will lose clarity by seeing its own heat unless it's cooled to cryogenic temperatures.
Illumination
You can invisibly illuminate a scene with an infrared light, making it easier for an infrared camera to see a larger scene. Since a low-light camera is sensitive to visible light, attempts to create additional light will give away the location of a hidden camera.
Tags: low-light camera, visible light, camera needs, camera sensitive, camera will, infrared camera, warm objects