Wouldn't libraw and/or freeimage be a good fit (both for raw and dng)?
Re:How to use the Python Imaging Library
by wiredfool on Friday November 08, 2013 @12:03PM
(#6697399)
I just found libraw yesterday. Looks interesting, and I have no objection to pulling it in as an optional dependency. Pull requests accepted. :>
Freeimage looks like more than we'd need, and includes libraw. And actually, looks like it does a lot of the same things that Pillow does, wrt to various image formats.
I make no promises :-/
Surprised you weren't aware of libraw (assuming DNG/RAW has been a requested feature for Pillow) -- but great it's on your radar now. FWIW libraw does an excellent job of handling RAW/DNGs -- as far as I know it's still the best tool for that (including various closed tools).
But once you have that file format, camera manufacturers tend to embed hunks of data in the raw file about settings and other things that the camera knows about the image, like the focus points, white balance, camera calibration, image compression, dot layout and all that.
I'd like to leave that as Someone Else's Problem. (unless there's a lot of money and shiny cameras in it for me)