Linking dng files with jpegs

Question

Hello all
Back in my Powerbook G4 days I had a habit of shooting cr2 with my Canon 5D but converting the cr2 file to DNGs and importing the latter into Aperture 1./2. But they were very slow to load so in the end I abandoned a raw workflow but still choose to keep the raw files. I shot jpeg+cr2, converted the cr2 files to dng, deleted the cr2s and imported the jpegs to Aperture. The DNGs were just kept on my external but never imported into Aperture.
Fastforward to 2012 and I have a highend RMBP and thought it would be fun to reimport those old dngs and wondered if these could be matched with the jpegs and treated as one file (with options to work with RAW or JPEG). Is there a way to do this? I thought I read somewhere that in Ap 3 you can break up and re-pair raw+jpegs. Just not sure if I can do that with dng+jpeg when the original combination was cr2+jpeg. The exif data will be the same but the DNG file created/modified/opened dates in Finder are all based on when they were converted.
I experimented with importing two of them into the same project as the original jpegs. When I sort by date they do not show up but when I sort by file you can see them beside the jpegs. Sorted by date I can only click on the jpeg file and right clicking does not give options of new version from master/jpeg so it is not linking them.
Any thoughts on how to do this or how best to fudge it?
Thanks
Ross

Answer 1

It depends on how you define a raw format. As far as the Camera Raw adjustment controls are concerned, you cannot tell the difference between a linear dng and "raw data" dng, since all the current Camera Raw adjustment controls happen after demosaic step.
(Both Canon and Kodak have cameras that produce demosaiced "raw" file formats in some cases. In Canon's case, the new "sRAW" format is already demosaiced. Some Kodak cameras (e.g. Kodak 14n, etc.) also saved a "lower resolution" raw format that was also demosaiced.)
The dividing line between a "raw" format and a "rendered" format is with whether the data stored in the file is scene referred or output referred. As long as the data is in a scene referred color space, it is easy to change the white balance, exposure, tone curve, etc. Once the data is converted to an output referred color space, it gets much harder to change those parameters without causing artifacts.
That said, it is better to keep the image in mosaic format if possible, since this allows you to take advantage of better demosaic algorithms in the future. For this user, that is not possible because Camera Raw 2.4 does not have a demosaic algorithms that works for the Fuji S5, so using the linear form of dng solves that problem.