Greetings, I have created a related ticket with the lensfun project:
https://sourceforge.net/p/lensfun/bugs/78/ This really only matters for VignettingCorrection: 1. If the assessments of your references are true that TCA (LateralChromaticAberration) are always baked into the ARW then the lensfun data will have been measured with TCA pre-corrected by the camera and lensfun data will only compensate for the difference between the in-camera precorrection and hugin's (lensfun's) idea of how much TCA should be compensated. 2. Distortion is never baked into the ARW, so the lensfun corrections can safely be applied to undistort images. 3. I have some images where shading compensation was on in-camera and then applying the full correction in darktable based on lensfun data would lead to over-correction. The workaround is either to fake a smaller aperture setting in the lensfun module, or to turn vignetting compensation off for now, which is a nuisance. What needs to happen on darktable's end, code-wise, to: 1. expose the 0x2011 EXIF tag contents to lensfun to assist it in picking the right of two alternate correction sets? 2. until the day that lensfun supports this (see ticket URL above), automatically flip the switch for vignetting compensation to "off" in the lens correction IOP? I'm willing to help with code on both lensfun's and darktable's end, and am proposing a Git feature branch tracking the development branches. I've been programming C for 25+ years and to some limited extent C++ w/ STL, and Python 3 for a few years, too. I think as a workaround for the time being the only way I have is to alter the lens names (add "VignPreComp" to the name, or similar) and manually choose them, to go along with datasets that compensate for the delta between the in-camera pre-compensated vignetting, and the full compensation. This can then be re-written properly once lensfun exposes a way to choose from alternate data sets for the same lens. Cheers, Matthias ___________________________________________________________________________ darktable developer mailing list to unsubscribe send a mail to darktable-dev+unsubscr...@lists.darktable.org
