Hi All - I've been playing with an infrared R72 filter from Hoya fitted to a Canon 50mm 1.4 prime lens. As the sensors in digital cameras are protected by a filter to remove IR light, using an IR filter to record IR images requires considerable exposure times, perhaps as much as 30 - 60 seconds. However, using the Canon 1.4 lens and a high ISO rating reduces times to about less than a second in good light. As described elsewhere on the Web, there are problems with focusing and with "hotspots" on some lens (including the Canon 50mm 1.4). To compound matters, the resulting images show a strong red or magenta bias which causes problems for post-processing. It's a wonder anyone bothers with the technique. Nevertheless, there are some fine and intriguing images to be seen and knowing how to capture them is always worthwhile.
I'm particularly indebted to Steaphany on this site for posts about a year ago on how to go about post-processing captured images. Until reading those posts I was struggling to get anywhere. The following image is the best of my first attempts and for anyone with a Canon DSLR and its associated DPP software here's a workflow.
Because the captured images have a strong red bias, it is very tempting to try and correct the white balance to give something more palatable. I spent a great deal of time on this and basically got nowhere. Having I read Steaphany's posts, I scrapped any idea of altering white balance. Instead, using DPP, switch the Picture Style to monochrome, adjust either in RAW and/or in RGB modes the exposure, dynamic range, contrast, highlights and shadows to give a workable image. Use the histogram to check the exposure. Increase Sharpness and check Noise Reduction, with values of perhaps 3 to 6 being appropriate for the level of noise encountered in these images. When satisfied, process via Convert and Save to JPEG or TIFF formats and open in your favourite editor. Further processing to enhance contrast seems to be necessary and you can use Levels and Curves to that effect. Some more sharpening may be appropriate. Finally, as an option and as I have done in this case, you can use an Orton effect to add a touch of glow to the image.
I'd be happy to hear from anyone else with a Canon DSLR who has tried this aspect of photography, and thanks again to Steaphany.