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Lens distortion measured for several 90-degree lenses.

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  • #16
    [QUOTE=nutsey;n6017]I measured the lens distortion (using this method) of 90-degree versions Git2P and 7S action cameras as well as some other popular low-distortion lenses.
    :
    GitUp Git2P (4.1mm lens):
    Click image for larger version Name:	2.png Views:	1 Size:	374 Bytes ID:	6019
    a=-0.0016663
    b=-0.0175647
    c=0.0217117


    Regarding these numbers. They look like the standard lensfun distortion numbers. Does that mean if I use the figures for 16:9 photo in darktable, that the lens distortion will be correctly applied? That is, the numbers describe the actual pattern of distortion and not a figure *only* based on 4:3 photo?

    THanks in advance for your reply

    Comment


    • nutsey
      nutsey commented
      Editing a comment
      I think these numbers can be used for both 4:3 and 16:9 aspect ratios due to the way they were measured.

    • independent
      independent commented
      Editing a comment
      > aspect-ratio>number</aspect-ratio>
      > This is the aspect ratio of the camera with which all shots for computing distortion models were made. It is the ratio of the longer edge to the shorter edge. Lensfun needs the aspect ratio internally for correct application of the distortion parameters. You may give it is as a real number or as a ratio with a colon like “4:3”. It defaults to 1.5 or 3:2.

      I got this quote from the lensfun manual, http://lensfun.sourceforge.net/manual/el_lens.html

      It seems the distortion is implicitly declared at the time of measuring the distortion, so 4:3 for the numbers above?

      As an aside, when reading about various camera raws it seems as though panasonic is one of the only camera manufacturers making raws in different aspect ratios.
      Last edited by independent; 03-20-2018, 08:14 PM.
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