Hi Martin! This workflow has been near to my heart for several years as the Technical Director on a stop-motion television show.
As Kirk mentioned, the rawtoaces utility is a great step in the right direction but unfortunately still contains a bug that may prevent it from being the right tool for you - when converting from a raw file like .CR2 to a floating-point .EXR, any highlights that fall above 1.0 on the brightness scale will be clipped rather than preserved as overbrights. The colorspace will be correct for ACES AP0 but you will lose the original latitude available in the .CR2.
The only fully workable method I have come across is to use the Cinelog-C color management plugins for Resolve or Adobe After Effects made by @cinelogdcp. I’m not positive about Resolve, but it is possible in After Effects to import .CR2 sequences through the Adobe Camera Raw importer using Cinelog’s digital camera profile, and then use the OCIO plugin to convert from Cinelog to ACES AP0 or AP1 and export to .exr.
This requires your project to be set to 32-bit with no working color space, and your output module to be set to .exr and “Preserve RGB” checked in the color settings. At that point you still won’t have a 100% to spec ACES file because it will be missing the ACES chromaticities metadata, but the pixel data should at least be correct. There might also be one more step needed in the OCIO plugin based on a conversation I had with @cinelogdcp over email but I never got around to determining that for sure.
Lastly, when making any sanity checks using these tools you may be caught off-guard by your ACES images looking just a stop or two dark compared to Adobe Camera Raw’s other camera profiles, OSX Finder, or the in-camera JPG images, even after you’ve properly applied the ACES RRT+ODT. This is normal, and you can find out why in the first two posts on this thread.
So far ACES hasn’t been the right workflow for our show because of these difficulties, but I’ve been waiting for a chance to experiment with it on a project of lower stakes so I would be happy to answer any questions you have if you still feel like trying it out. Just keep in mind that with the above-mentioned issues that you may need to do a lot of double and triple-checking to be sure that you really are getting correct ACES images.