Discoverd today that if you have CS2 you cannot load RAW files from the 40d
There has been a update for ACR (adobe camera raw) to support this camera but it is only compatible with CS3 and there will be no update for CS2 so it looks like to me that adobe are pushing the use of DNG.

So it looks like the only options are:

1. Use canon DPP (it comes with the camera) to output TIFFs
2. Use the free adobe DNG converter to convert the CR2 files to DNG, then use CS2 to open the DNG files.
3. Buy CS3

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Cameras: Canon 1dmkII x2
Canon lens: 17-40 f/4 L, 24-70 f/2.8 L, 24-105 f/4 L, 70-200 f/2.8 L, 100-400 f4.5-5.6 L
Other Lens: Sigma EX 105 Macro
Accessories: Elinchrom skyport
Flash: 580ex, 430ex.
Studio Lighting: Elinchrom strobes, prolinca and Elinchrom softboxes.