Hallöchen! Kelvie Wong writes:
> I just realized that on my Sony a7R II (and this probably applies > to all of the cameras in this series, probably even the NEX), if > you have certain camera settings, some lens corrections are baked > into the ARW files (Sony's raw format) -- that is the bit values > appear to change, not just the metadata. I know this behaviour from my NEX 7 from 2012. Vignetting correction is applied to ARWs. You cannot switch it off only for ARWs, which is very unfortunate for a mostly-JPEG shooter like me. Anyway ... this is the reason why http://wilson.bronger.org/lens_calibration_tutorial/#id3 explicitly says “Make sure that no corrections are applied by the camera (some models do this even for RAWs)”. > [...] > > The two corrections affected are vignetting corrections (Sony > calls this Shading Compensation), and CA corrections. This is hilarious of Sony. Really. Re-scaling of RAW data (for vignetting) is bad enough, but re-*sampling* is absolutely shocking since many parameters affect the output: Crop or leave black spots, Lanczos or cubic, which channel to keep unscaled? And no user interaction possible ... this has nothing to do with RAW anymore. And if they don't resample but desaturate edges, one has even more parameters. And this is for sure? The µ43 people at least only make sure that all commercial RAW converters apply the corrections implicitly (so that the user sees the strong distortions only with great effort) but at least, they don't actually touch the RAW data. > [...] > > Now, in an ideal world, we would instruct the user to always turn > these off, and apply lensfun corrections once, but perhaps an even > better approach would be to have the lens correction module *not* > apply TCA and vignette corrections depending on whether or not the > EXIF data says it has already been applied. Maybe. This is Darktable domain rather then Lensfun domain. Tschö, Torsten. -- Torsten Bronger ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
