Since upgrading to Aperture 3, I have had serious problems with the rendering of Canon EOS 5D (not Mark II/III) RAW files. With Aperture 2, both the preview and full-sized images looked basically the same as the original images as displayed on the camera's display, without any adjustments.
With Aperture 3, each preview images initially look fine after import, but when Aperture re-renders it from the RAW file (e.g. when displaying the full-size image), the colors are drastically intensified, and the hue is shifted generally towards green/blue. I've checked the RAW Fine Tuning, and it is set to the defaults. If I turn the default RAW Fine Tuning settings all the way down, the image is still not at all like the preview from the camera - it becomes much darker and stays too blue/green, with washed-out colors.
A friend with a Canon EOS 5D MkII also recently upgraded her Mac from Aperture 2 to 3, and hasn't experienced any problems. We've tried importing RAW files from my (non-MkII) camera to her Mac (with the default RAW Fine Tuning settings), and get the same results as with my own Mac (i.e. strange colors), so the problem seems to be related to the camera model.
I've also noticed that scanned greyscale tiff images (including images that were originally imported under Aperture 2) are changed when first displayed by Aperture 3 - they become darker and more contrasty, with lots of information lost in the shadow areas.
I've also tried removing Aperture preferences, Aperture itself, and re-installing from download, with no change in the problem. (Aperture is the current latest version, 3.3.2.)
Has anyone experienced similar problems?