On samedi 25 juillet 2020 11:37:47 CEST Felix E. Klee wrote: > Terry Pinfold <[email protected]> > > writes: > > I tested the image on the latest Windows version of DT and the auto > > correction options worked well for me. > > Thanks for trying it out. Here is my result with Darktable 3.0.2 on > Windows 10: > > https://archive.org/details/p-1100853-corrected > > I don’t like it. The dominant vertical lines on the left and the right > side of the image are not straight. One problem is that they’re bent > due to optical distortion and maybe also due to construction. Still, I > think having the top and bottom points aligned would look much better. > So if I could draw two green lines manually, then this would be a quick > solution. > > > You can put guides on and use manual slider controls to set yourself > > if you prefer. > > I know, but it’s no fun. Darktable is sluggish on my machine (i7-8650U, > 16GiB, Intel graphics). > > > Applying specific lens distortion correction first may help improve > > final result, but I was pleased with the job auto did. > > Yes, with that camera lens distortion correction is needed. The lens, > as far as I know, is identical to that in its predecessor, the DMC-FZ5. > > This image of course is not great anyhow, having flare and bad contrast. > Nevertheless it’s good for illustrating my issue with perspective > correction in Darktable. > > > BTW, GIMP has very good manual perspective tool options if DT result > > is not to your liking. > > That takes too much time, plus it’s destructive. I want to process > images quickly.
You can try the "crop and rotate" module, with the keystone option. You set 4 points, defining 2 lines that should be vertical, or 2 that should be horizontal (or both). As there's no interactive correction, that is fast. Click OK and the correction is applied. Then you can crop as wanted. Of course, that won't take care of the curved verticals, either, but that's a job for the lens correction module. Remco ____________________________________________________________________________ darktable user mailing list to unsubscribe send a mail to [email protected]
