On Thu, Jul 21, 2016, at 10:26, Torsten Bronger wrote:

> > As a side note, while you're updating the profiling instructions,
> > it might be worth expanding a little on the importance of
> > profiling vignetting at different focus distances depending on
> > lens type. I found, for instance, that applying the correction for
> > infinity produced really bad overcorrection at close focus
> > distances on the Olympus M.25mm F1.8, but I'm not sure how
> > generally this is true of similar internally-focusing
> > lenses... and I'm guessing that for external-focus types probably
> > it's a non-issue, as implied in the current tutorial...
> 
> People who see a problem should consider sending sample images.  I
> don't want to give the impression that it is important because it
> would raise the theshold for vignetting images even higher.  It is
> difficult to get people doing this.

That's understandable, although I somewhat suspect that the biggest hurdle for 
people is getting set up to take the vignetting images in the first place...

Anyway, after my first attempt at attacking the backlog, I have a few 
comments/questions:

Regarding the calibrate.py script, I had an "interesting" time getting the 
dependencies in line... it seems that it's been active times in the world of 
linear algebra software lately, involving much breakage of backwards 
compatibility... to make a long story short, I had to fall back to older 
versions of numpy and lapack (1.8.2 and 3.3.1, respectively) to build a scipy 
that played nicely with the script... in case that's useful information for 
anybody else trying to make it work. Also, the link to information about names 
for makers and mounts in the the script is 404, and since it's a shortened 
link, I'm not sure what it pointed to, exactly.

Rather than do a full checkout of the ownCloud repository, I just downloaded 
the directory I wanted, then uploaded the resulting lenses.txt and lensfun.xml 
files after calibration, as well as moving the files to a newly created 
"distortion" directory, all using the web interface. Since the same files were 
used for tca, I just created that directory and left a note in it to that 
effect, rather than duplicate the files. The instructions seem to indicate that 
uploading the other resulting files (.pto, etc) isn't desired, so I didn't. Is 
this ok, or should I do something differently?

Also, found this tutorial helpful, and didn't notice them linked in any of the 
instructions:

 http://hugin.sourceforge.net/tutorials/calibration/en.shtml

Since recent hugin versions don't display the correction parameters in a 
copy-friendly manner, I just exported an .ini lens data file for each of the 
focal lengths, then used the attached quick'n'dirty script to scrape the data 
into the lenses.txt file, in case anybody else finds that method useful.

I'll try to get to some more lenses once I'm sure I'm not Doing It Wrong.

Cheers!
jys

Attachment: ini2lensfun
Description: Binary data

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