Camera for Infrared Photography
Updated: Aug 8, 2021
This image is made with a camera with infrared filter fitted inside.
This image is made with unmodified camera with infrared filter in front of the lens.
Almost all cameras are equipped with IR-cut filter in front of the sensor. It is also called as a 'hot mirror'. It is supposed to cut down the "infrared pollution" from normal light. Ideally this filter should be removed so as to enable your camera to receive good amount of infrared light or radiation. but this is major alteration in the camera which voids the warranty and removes the function like dust removal from your camera. This can still be used for normal photography and this type of modification is called 'full spectrum' since it allows not only infrared, but also normal light and ultraviolet light too. With various filters such a camera can be used for all kind of photography. If the camera being converted is a DSLR type, normal viewfinder cannot be used, because the filters fitted in front of the camera do not allow normal light, only 'live-view' screen can be used for composition. Mirrorless cameras with electronic view-finder have the distinct advantage here.
If infrared-pass filter is fitted in the place of hot mirror, the camera becomes 'only infrared' all the time. It obviates the need to use the filters and view-finder of such a camera can be used as the normal camera. Of course, additional filters with higher cut-off frequency can also be used in front of camera and again only live-view screen needs to be used for composition.
If one does not wish to make such radical changes in his/her camera, the normal camera can still be used for infrared photography. The hot mirror, though designed to cut down all infrared light, does not do so completely and let in some amount infrared light. Older generation cameras usually have weaker hot mirrors and let in much more infrared light than the newer ones. If IR pass filter is fitted in front of the lens, it blocks all normal light and the image can be made with whatever infrared light trickles in. Of course, since the quantity is very less, long exposure and use of high ISO becomes necessary.