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m4/3 Lens Correction

BobRockefeller
CO9 detects my Olympus OM-D E-M1 and lens combination and pre-selects them in the lens correction tool, just as it should be.

But all the sliders are set a 0%.

Is 0% standard correction (perhaps that which is supplied in the RAW by Olympus)?

Or is 100% standard?
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Comments

8 comments

Date Votes
  • Christian Gruner
    Short answer: That depends on the amount the lens distorts. If the lens doesn't distort much, CO will set the slider at 0% as default.
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  • BobRockefeller
    [quote="Christian Gruner" wrote:
    Short answer: That depends on the amount the lens distorts. If the lens doesn't distort much, CO will set the slider at 0% as default.


    Thanks!

    So am I to presume that a lens with "more" distortion would cause CO to pick a higher number?
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  • dee jjjaaaa
    I never saw any cases with some odd % though... I think P1 people shall tell you if 100% corrections is what Olympus firmware puts in a raw file or not and 0% is no correction at all... may you be can compare C1 with 0% and 100% vs some converters that are know to either not do correction at all or you can reliably switch it off (easiest way is dcraw command line) or do exactly as firmware suggests by embedding the data in raw files (like ACR/LR) w/o options to control of the %
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  • Christian Gruner
    [quote="BobRockefeller" wrote:
    [quote="Christian Gruner" wrote:
    Short answer: That depends on the amount the lens distorts. If the lens doesn't distort much, CO will set the slider at 0% as default.


    Thanks!

    So am I to presume that a lens with "more" distortion would cause CO to pick a higher number?


    Nop, current implementation is on/off to 100%, when above the threshold.
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  • Christian Gruner
    [quote="deejjjaaaa" wrote:
    I never saw any cases with some odd % though... I think P1 people shall tell you if 100% corrections is what Olympus firmware puts in a raw file or not and 0% is no correction at all... may you be can compare C1 with 0% and 100% vs some converters that are know to either not do correction at all or you can reliably switch it off (easiest way is dcraw command line) or do exactly as firmware suggests by embedding the data in raw files (like ACR/LR) w/o options to control of the %


    All the profiles for Olympus and Panasonic lenses in CO are made by Phase One here in Copenhagen.
    0% correction is indeed no correction at all, and 100 % is a complete correction.

    The threshold dictating when to auto-correct is also set by Phase One (and was actually raised/eased a bit in CO7).
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  • BobRockefeller
    Good information, and thank you.

    Out of curiosity, why would full correction not be the default? That would seem to be the expected behavior.
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  • Christian Gruner
    3 reasons:
    1: Not every picture needs or benefits from correction
    2: Correction has a very small image quality penalty. Very small, but it is there
    3: The cropping that also happens when correcting, has been a source of confusion, especially among new users, which was, in part, why the threshold was raised.
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  • dee jjjaaaa
    thank you for the more detailed answer !
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