Options for an IR camera conversion

QWith spring not too far away, I have decided to get my old, and now unused, Canon EOS 450D infra- red converted. I’m interested in both false colour and mono infrared. What are the best options for tailoring the camera conversion for these goals? I’m not all that clued-up on the ‘nanometre’ range to aim for. If you have any other tips, I’m all ears! Fabian Priestly

ABasically, camera manufacturers filter out infrared (IR) because digital sensors are sensitive to it, and this can interfere with visible light image recording. A block of IR blocking glass is placed in front of the sensor, often called a ‘hot mirror’. There are three ways to approach the task of converting a camera for IR photography. The easiest, cheapest, but least desirable method is to slap an IR filter on the end of a lens without converting the camera. This results in very long exposure times and a very dark viewfinder, even when using live view.

Two camera conversion routes are available. First, let all light through to the sensor, including IR, by replacing the hot mirror with clear glass. Second, replace the hot mirror glass with glass that only transmits light in the required wavelength. With the first method you need to place an IR filter on your lens, but DSLR viewfinder darkness can be a problem, though this time you can use your camera screen in live view. If you are ambitious enough, the first option gives you the freedom to use different IR filters for different projects.

Adapters may be needed if lens filter sizes vary. It also means the correct filter will enable the camera to shoot normal visible light once again. The most versatile IR filter is 720nm. This transmits just enough of the visible light spectrum to enable vibrant false- colour IR images to be produced and at the same time allow effective mono IR conversions. Lengthen the nanometre figure to optimise for mono IR photography and reduce it if you want to play with more visible colour.