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Aftershot Pro lens correction profile

Discussion in 'Image Processing' started by Tom_Chan, Jul 13, 2014.

  1. Tom_Chan

    Tom_Chan Mu-43 Regular

    Aug 19, 2013
    Palo Alto, CA
    I'm quite sure this question has been asked before. I dropped Windows for years and I use Ubuntu only so I grabbed Aftershot Pro since it runs on Linux. One thing that annoys me though is the lack of lens correction profile for most of my lenses. I'm using, the latest version before AfterShot Pro 2. The only calibrated lens for me is P20. P12-35, O12-50 and O40-150 are uncalibrated.

    According to Photozone.de reviews, when uncorrected,
    1. for O40-150, the wide end has -4% barrel distortion, while 70, 100 and 150 have <1% distortion which I can live with it.
    2. for O12-50, the wide end has -6.9% barrel distortion, 0.1% at 25 and 1% at 50.
    3. for P12-35, the wide end has -5.8% barrel, -1% at 20 and 0.7% at 35.

    Can someone refer me to where I can find the correction coefficients, or do I have to do it myself? Thanks in advance.
  2. mcasan

    mcasan Mu-43 All-Pro

    Feb 26, 2014
    Both Aperture and LR read the lens correction data that should be passed in a M43 raw file. That is why you will not find lens correction tables/listings for M43 equipment for LR at Adobe.....no need. I would ask Aftershot Pro folks why they are not reading and using the lens correction data in M43 raw files.

    If you are running Linux, consider a Mac or a Hachintosh so you can use a far wider range of photo editing tools. I understand about Windows. I dropped it as soon as I retired 2 years ago. I was so glad to get back to Mac. My previous Mac was my first one back in 1984.
    • Like Like x 1
  3. Tom_Chan

    Tom_Chan Mu-43 Regular

    Aug 19, 2013
    Palo Alto, CA
    I'll reply myself. I got the Panasonic 25mm 1.7 this week bundled with Corel AfterShot Pro 2 so I did some more research. Turns out there's a project called lensfun and it contains the correction parameters for a lot of lenses. However when I started this thread the P12-35 lens is not there (it's added to the library a few months later). Now AfterShotPro 2 also has the correction profile for P12-35. The parameters are different and I'll have to see which is better.

    The other thing to report on is the auto detect in Lens Correction in ASP 2. Even with the lens profile it does not detect it correctly, so I did some digging. Turns out in Mac Preview the "Lens Model" is "Lumix G Vario 12-35/f2.8" whereas the one in ASP 2 lens database ("/Applications/Corel AfterShot 2 (64-bit).app/Contents/Resources/supportfiles/Profiles/LensProfiles/profile_micro43.txt") is "Lumix G Vario 12-35mm f/2.8". Changing the entry to "Lumix G Vario 12-35/f2.8" enables it to be correctly detected.

    Looking at the LensProfiles folder for some of my lenses I found some have (0.0, 0.0, 0.0) as the a, b, c parameter which is definitely not right... so you might as well replace these by the values from lensfun.

    Now I need correction profile for the new Pana 25mm f/1.7... (if distortion turns out to be small that'd be nice and I don't need to correct for that)
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