Canon what Mark IV? EOS-1D?
You can find out what versions of Camera Raw support what cameras here:
Note that Photoshop CS3 supports only Camera Raw 4.x. EOS-1D Mark IV requires 5.6.
You'll have to use the free DNG Converter solution provided by Adobe since your camera requires Camera Raw version 5.0 or newer to directly open its raw files.
Or, as you say, upgrade Photoshop to a version that directly opens your files for the most convenience and best image quality.
Noel Carboni wrote:
I did see, as I was researching my response, that there's only one model that has reached Mark IV stage so far, so my question wasn't completely necessary. I have been anticipating a 5D Mark IV at some point to counter Nikon's latest offerings.
You may need to wait a while since the 5D Mk III is baely out of the starting gate.
The reviews seem to all say that the 5D Mk III is blowing the competition out of the water. I an't verify that since I use a 7D.
BTW, I would recommend upgrading to CS6 as opposed to using DNG converter. The new features such as the automatic CA correction, lens corrections, and better noise reduction make it worth upgrading.