I am trying to determine the vignetting corrections for a new lens (Laowa 7.5mm F2.0 MFT) using using the lens_calibrate.py program and images taken through a translucent sheet. I appreciate that with a very wide angle lens like this it might overestimate the vignetting, but that is not the problem. I run the program and get the lensfun.xml file which I then add to the lensfun database (there is already an entry there for this lens for chromatic abberation and distortion). If I then use darktable to apply this correction to either the .pbm or .pgm files produced by lens_calibrate the correction is very good (as it is for a 16bit tiff exported directly from the demosaiced raw without any other processing) However if I apply it to the original raw file (Olympus .orf) the correction is very poor with only about half the degree of correction required being made (though it does seem to be consistently out by proportionally the same amount). Thinking this might be a darktable problem I then tried rawtherapee and ufraw, but they both had the same problem with the raw file. Does anyone have any ideas what might be going on, or has anyone seen anything similar? Obviously I will raise this with darktable developers (my preferred application), but given that rawtherapee and and ufraw behave in the same way there may be a generic problem.
regards, Jim
_______________________________________________ Lensfun-users mailing list Lensfun-users@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/lensfun-users
