Most cameras work in much the same way; light reflected by objects enters through a lens onto an image sensor, which converts the light to digital values and creates an image. The amount of light hitting the sensor determines the quality of the image. If there is not enough incoming light, the sensor will not register an image at all.
Axis Communications utilizes a technology called: Lightfinder. This technology is based on proprietary sensors and optics that create exceptional light sensitivity. The camera is able to deliver an image where the use of a standard network camera would not be possible. Lightfinder is also able to provide good color reproduction in a low light camera deployment.
Another solution is to install auxiliary lighting in your low-light areas, to illuminate parts of the scene that are too dark. Adding extra lights widens your range of camera options.
Another option is a thermal camera, which contain a special sensor that registers heat and forms an image based on the temperature variances in the scene. Footage from these cameras lack natural colors, but are useful for detecting objects in absolute darkness. Learn more about thermal imaging below: