On Tue, 2011-07-26 at 22:59 +0100, Stefano Rovetta wrote: > > I can do the lens correction with ufraw manually, but there > > are three > > parameters, and it is hard to figure out how to adjust them > > visually. > > After a very quick googling I landed here: > http://wiki.panotools.org/Lens_correction_model > > As far as I can understand, this is the model used by UFRaw. > > You might calibrate the parameters for each of your lenses with the aid > of the model and some reference image (e.g. you can print a grid > on paper and take a photo with your lenses, setting the zooms at > significant positions like max wide/max tele/center). > > Then you can guess the parameters by analyzing the correction formula, > or you can even write a distortion measure and minimize it analytically > - I am sure you have the necessary background to do that, and it can > even be fun to do it.
Actually, I am familiar with the lens model, and at one point I tried to calculate the coefficients for a lens I had. It is not conceptually difficult, but it is harder in practice to do than one might imagine. I would rather not do it if it has already been done. As I remarked, the gimplensfun filter does a very good job based on what it finds in the exif file, and it works very well for my 18-200 mm Nikkor lens. So ufraw should be able to do as well. I think it is bug in ufraw and I hope someone will fix it soon. > > _______________________________________________ > Gimp-user mailing list > Gimp-user@lists.XCF.Berkeley.EDU > https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user -- Leonard Evens l...@math.northwestern.edu Professor Emeritus, Department of Mathematics, Northwestern University _______________________________________________ Gimp-user mailing list Gimp-user@lists.XCF.Berkeley.EDU https://lists.XCF.Berkeley.EDU/mailman/listinfo/gimp-user
