On Fri, Nov 18, 2016, at 06:14, Chris Chiappa wrote:
> > I have the Oly, and it's a great little lens, but does need a fair > > amount of correction, which is well provided for in lensfun currently > > (I spent some time getting the vignetting right, which varies quite a > > bit with focus distance, in such a way that always applying the > > correction for infinity does some not-so-nice over-correcting at close > > range). > Hi, I believe that I was the one who submitted the original data for > this lens. I only calibrated at infinity because my camera at least > (Panasonic GX-7) does not seem to record the focal distance anywhere I > can see in the EXIF. Do other cameras do better here, or do you just > do a lot of manual fiddling with the correction? The Olympus E-PL6 gives reliable values for focus distance in exif tag 0x0305, which at least exiftool knows about: http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/Olympus.html I don't know about previous Olympus m43 models, but I do know that while the field existed in my XZ-1 and XZ-2 compacts, it was pretty much garbage. It's useful information for vignetting correction on at least *some* lenses, so hopefully it will become common. There's no similar FocusDistance tage listed for Panasonic, though, as far as I can tell: http://www.sno.phy.queensu.ca/~phil/exiftool/TagNames/Panasonic.html although I suppose it's possible that it exists but hasn't been "discovered" yet... Incidentally, I've been using the following correction line in my personal lensfun database for the 25/1.8, it uses the simpler, less computationally expensive poly3 model, which seems well suited to the distortion of this lens: <distortion model="poly3" focal="25" k1="-0.002282"/> If you agree that it performs well, it could be swapped into the official database... -- jys ------------------------------------------------------------------------------ _______________________________________________ Lensfun-users mailing list [email protected] https://lists.sourceforge.net/lists/listinfo/lensfun-users
