How do I decide between “RAW as Master” and “JPEG as Master” when importing RAW+JPEG into Aperture?

Question

I guess this comes down to an Aperture question and a more general post-processing question.

I've been shooting RAW+JPEG and importing both to Aperture with the RAW image set as the master. But I've noticed that in low-light or high-contrast photos, if I switch the JPEG to master the photo "looks better".

Why does the version I set as master affect the appearance of the photo in my library in Aperture (where does the other one go exactly)?

And why does the RAW image seem to look worse in these situations? How can I figure out approximately what the camera did for the JPEG so that I can best process the RAW image?

Answer

The Aperture software display the one that you selected as master with the applied changes. If you compare an imported RAW with a JPG, Aperture treats them a little bit different. That is until you make any changes that is. When showing a JPG imported image, the camera has already performed all the post processing, like white balance adjustment and in some cases noise reduction. The RAW image is only corrected with "RAW fine tuning". It does not have any noise reduction or sharpening and stuff. Therefore you have to work more with the RAW image than the JPG image. The reason for cameras to have a JPG + RAW mode is for you to get a quick way of getting a usable image without doing any post processing.

I think it is impossible for you to figure out how the camera did to convert from RAW to JPG. However you could test the preset "Auto Enhance" which could give you similar result. It perform things like sharpening and adjusting the colors of the pictures. Note that the noise reduction is not adjusted when applying "Auto Enhance".

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