Notes

Digital infrared images

July 2007

I have had various experiences with the world of infrared (IR) photography. The first was with Kodak High-Speed IR film, which turned out to be frustrating. The second was with Ilford's extended red-sensitivity film SFX, which was easier to handle and gave more satisfactory results. This is still available at the time of writing, having been re-introduced by the resurgent Ilford company.

However, the rise of digital photography offers a potentially less painful route and a couple of years ago I reviewed the options, updated with the current text. So the technical routes to digital mono IR images seem to be:
  • Take coloured images and use an image manipulation program such as Photoshop to mimick the effect. Entirely possible, but unexciting as at comes down to faking it.
  • Customise your DSLR camera by having the IR filter removed and replaced with plain glass, then place a visually-opaque filter on the front of the lens. Expensive, as well as leaving you with a camera that is dedicated to IR.
  • Use an IR specialist camera (such as the recent Fujifilm IS-1 in the US). I think that the cameras in question, designed for forensic and scientific work, are only available in the US.
  • Use an older digital camera, some of which are far more sensitive to IR than the current machines.
To cut a long story short, I went for the final option and chose the Minolta Dimage 7. This met my criteria:
  • A camera that could be hand-held in bright sunlight
  • It must be possible to see the IR scene on the EVF and screen
  • A high-enough resolution to give good-sized prints at A4 and slightly above
  • A reasonable zoom range
  • It could revert to a 'standard' visible-light digital camera
The 5-megapixel Dimage 7, a bridge camera with a built-in 28-200 (35mm equivalent) zoom, was introduced around 2001 in the UK, with a list price of around £1000. However, with the price of digital cameras plummeting over the past few years, I was able to buy one second-hand for £150 in 2005. A much more reasonable sum.

This camera has a comparatively-weak internal IR filter, which Minolta 'rectified' on later models as users complained about getting too much red in their images. Nevertheless, despite the 'weak' internal IR filter, the camera still loses around 7.5 stops of light. So I placed a visually-opaque Hoya R72 filter on the front of the lens and away I went (note that it is easy to remove the filter to get a standard digital camera). The following settings are the result of practical experience, in hand-held use in bright sunlight (the best conditions for IR work anyway):
  • Use RAW for the best image quality
  • Set the ISO to 200 as the best compromise between noise and the ability to hand-hold
  • Set the WB to 'Sun' for standard treatment between shots
  • The camera tends to underexpose slightly and not fully utilise the right-hand quarter of the histogram, so overexpose by 0.7 of a stop
  • Compose as precisely as possible, so as not to have to crop and lose pixels
Once an image is desaturated and converted from RAW, it is possible to mimick film-effects such as additional grain and glow. However, I find that images without this extra treatment look better.

There are additional issues if you want to take multiple images for stitching together as panoramas, but that's another story....

Finally, bear in mind that it is best to avoid taking images purely for the IR effect. The IR should be complementary to a strong composition – otherwise a weal image is still a weak image despite the novel technical effects.

Several images on this site were captured using this technique:
- 'The History Lesson'
- 'Magic Glade'
- 'A Forgotten Field'

Nov 2016

I have since had a Canon Powershot G10 converted to IR. This camera is an 'advanced compact', with a custom white balance function that makes this possible. Having a small sensor over-populated at 14 megapixels, this was not really satisfactory beyond ISO 200 as a conventional camera, because of noise levels. Indeed, the subsequent model in the series went back to a more realistic 10 megapixels.

But it is suitable for IR conversion, as most IR landscape images are shot in bright sunlight and this suits the ISO 100-200 operation of this camera. Shoot in Raw and in post-processing you can either flexibly convert to monochrome in ACR, or take it into Photoshop and swap colour channels for striking colour IR effects.