In infrared photography, the photographic film or image sensor used is sensitive to infrared light. The part of the spectrum used is referred to as near-infrared to distinguish it from far-infrared, which is the domain of thermal imaging. Wavelengths used for photography range from about 700 nm to about 900 nm. Digital camera sensors are naturally sensitive to the infrared spectrum. The have a filter over the sensor that blocks the infrared. A digital camera can be modified by replacing the sensor filter with one that blocks light in the visual spectrum.
I had the sensor of an unused Olympus EP-2 converted to infrared.
It's a different world.
