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EXIF JPEG Focal Length Confusion resulting in incorrect spans RRS feed

  • Question

  • Canon EOS 60D w/ EF-S 55-250mm IS II lens

    lens data: en.wikipedia.org/wiki/Canon_EF-S_55-250mm_lens

    www.usa.canon.com/cusa/support/consumer/eos_slr_camera_systems/lenses/ef_s_55_250mm_f_4_5_6_is?selectedName=Specifications

    I've been using Microsoft Image Composite Editor (ICE) for over a year to make hundreds of stitches.  Great program.  I almost always use it in the "Rotating Motion" mode.

    However, I've frequently been having issues with 360 degree panoramas; only rarely does ICE realize that it is 360 degrees.

    I suspect that the problem is related to an error in the interpretation of the jpeg EXIF "Focal length" tag.

    en.wikipedia.org/wiki/APS-C

    With this lens at 55 mm the horizontal field of view should be 23.33 degrees.  When I place two images into ICE so that I can see it's interpretation it says 14.1 degrees.

    My camera uses an APS-C sensor size which would make the 35mm film focal length equivalent lens 88 mm (1.6x lens marked focal length).  ICE does not respond to my filling in the "35mm focal length" EXIF tag with this information.  In fact, ICE's apparent interpretation of 55mm is going the other way (i.e. it's as if ICE is interpreting focal length from the perspective of a Nikon 1 or 4/3rd system).

    If the interpretation of EXIF "Focal length" can't be fixed it would be convenient for ICE to use "35mm focal length" when present so that I can manually correct it.

    Thanks
    Sunday, October 14, 2012 4:08 PM