The achievable ranges for different Raymax infrared illuminators are given below. The ranges shown indicate the maximum usable range of a single 850nm unit with a high performance camera. The figures given are for reference only. Distances achievable in practice will depend on a combination of camera, lens and infrared illuminator.
The intensity of illumination due to a given source is inversely proportional to the square of the distance from the source. [See Inverse Square Law.]
The use of two units will increase the maximum achievable range by approximately 40%.
[See Inverse Square Law.]
All these units [except the Raylux 25] have Ultimate Adaptive Illumination. In practice, it may not be necessary to use multiple illuminators to achieve increases in distance. Tighter angle devices, or more powerful illuminators can often provide the required additional power output.