#68 New lens: gitup git2

[Mark Hale]

Files already uploaded to calibration service.

[Mark Hale]

fwiw, here are my results:

    <camera>
        <maker>GITUP</maker>
        <model>GIT2</model>
        <mount>gitupGit2</mount>
        <cropfactor>5.56</cropfactor>
<!-- ccd diagonal 7.77mm width 6.216mm height 4.662mm -->
    </camera>
    <lens>
        <maker>GITUP</maker>
        <model>GIT2</model>
        <mount>gitupGit2</mount>
        <cropfactor>5.56</cropfactor>
        <type>equisolid</type>
        <calibration>
            <distortion model="ptlens" focal="3" a="-0.005" b="0.1" c="-0.57"/>
        </calibration>
    </lens>

[Mark Hale]

I tried out the submitted poly3 model: <distortion model="poly3" focal="3" k1="0.01419"/> and I found it didnt really correct the distortions. Perhaps a typo? decimal point in the wrong place?

[Torsten Bronger]

I don't know whether this solves your issue, but your entry is missing the aspect-ratio tag.

[Mark Hale]

Ahhhhhhh, I removed it because I was using darktable (2.0.6 I think) and it complained about the version 2 xml format, so I stripped out the extra stuff thinking it wasn't essential. There isn't a way to convert a k1 v2 value to a k2 version 1 value by any chance? Or what software do you use/should I use to read version 2 format? (windows/linux don't mind). Thanks!!!

[Torsten Bronger]

The aspect-ratio tag is available also in version 1 of the DB. So, unless you have a really old Lensfun version, just leave it in and use version="1".

[Mark Hale]

Ok, I'll try it when I get home later.

[Mark Hale]

So, I dl-ed and built lensfun 0.3.2, and linked it to darktable, and ran lensfun-update-data that dl-ed a version=1 actioncams.xml with the gitup entry including aspect-ratio into .local. Ran on darktable and tried the fisheye correction - still only see a slight correction to the curvature. I'm doing this with jpgs if that has any bearings.

[Mark Hale]

I've worked out where I was going wrong. The target geometry in darktable had defaulted to thoby fisheye, once I had set it to rectilinear my photos straightened up nicely! In hugin, I noticed I had both target and source geometry set to rectilinear. Once I changed source to equisolid, things looked better there too. A quick play with the optimizer and I got a b/k1 of around 0.016, close to yours, so I knew I was now doing it right. Many thanks!!!

[Torsten Bronger]

You are welcome. The “thoby problem” is due to a binary incompatibility between Lensfun versions. Actually, DT needs to be re-compiled. But nobody has reported crashes so far, only the thoby problem, and this is annoying but harmless.