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Fullframe or Circular

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  • Flemming V. Larsen
    ... From: Eric O Brien ... With the Tokina 10-19 mm lens PTGui set it up as a circular lens if I let it take the values from Exif. Which I believe is correct
    Message 1 of 3 , Apr 23, 2007
      From another thread:

      ----- Original Message -----
      From: "Eric O'Brien"


      -------------Snip---------

      > I'm using a Fuji S2 with the Nikon 10.5 lens.

      -------------Snip---------

      > Just IGNORE the focal length and focal length multiplier fields.
      > There is only one important value and it is "Horizontal Field of Field."
      >
      > For this lens, in portrait orientation, the value is somewhere near
      > 86 degrees. That is, the angle of view across the SHORT side of the
      > image is about 86 degrees. The other way, it's about 137 degrees.
      > Just set Lens type to Fullframe and HFoV to 87.
      >
      -------------Snip---------

      With the Tokina 10-19 mm lens PTGui set it up as a circular lens if I let it take the values from Exif.
      Which I believe is correct as it is a circular fisheye and that the same goes for Nikon 10.5.

      When I HDR-proces the photos before stitching and loose the exif data I can set it up as fullframe.

      I'm able to get a good stitch both ways, but the max pano-size is bigger for the fullframe setting!?
      (for 2000x1330 input ~ 5400 for fullframe and ~ 5050 for circular)

      I usually scale down to speed up things, so if I later want to make a fullscale is good to be able to reuse the pts-file.
      This is possible with Fullframe as it is set to "no crop". With Circular the crop-circle is around the photo only touching the corners, so you have to redo the cropping for new size.

      I think the fullframe is meant for corrected wide-angel , so my question is:
      Does ptgui/panotools handles the remapping in different way depending on the lens type and does it have any impact on the final projection of the panorama.

      Visually I do not notice any odities.


      - Flemming

      [Non-text portions of this message have been removed]
    • Milko Amorth
      Hi Fleming, ... In presets it assumes values for a preview. After optimising, no. A fisheye is a fisheye. All it does is define the crop format to maximize the
      Message 2 of 3 , Apr 23, 2007
        Hi Fleming,

        > Does ptgui/panotools handles the remapping in different way depending on
        > the lens type
        In presets it assumes values for a preview. After optimising, no. A
        fisheye is a fisheye. All it does is define the crop format to maximize
        the image fovs. The crop defines the fov of the image. A full frame
        fisheye becomes a circular fisheye image on a larger sensor. A circular
        fisheye becomes a full frame on a small sensor. The crop factor of the
        sensor will define the image area. The mapping is defined by the panorama
        setting output...rectlinear,cylindrical, psphere ect...


        > and does it have any impact on the final projection of the panorama.
        No. But dont forget to reoptimize.

        Here is a play for you:
        -Load a project, you know gives a great equirectangular.
        -Place the ptgui and the panorama editor window side by side on your
        screen.
        -Make sure only fov is checked for global optimization in optimizer tab.
        -Now play with the lens type input and crop settings and watch the preview.
        Go all out. Make a cicular fisheye to a full frame fisheye and over/under
        crop and vise versa.
        Make a fisheye lens to a rectlinear lens and crop it down to about 90° or
        100°.
        It will look weird in the panorama editor because the project values have
        been applied for the lens and crop settings.
        But reoptimization will bring it back to the set projection with the
        correct lens fov. Equirectangular from any lens type used.


        Cheers, Milko

        --
        Milko Amorth
        360° Immersive Imaging
        Photographic Virtual Reality
        VRCanada.ca
        604.561.5101
        Skype me @ vrdundee
        Member of IVRPA.org
        Contributor to the World Wide Panorama Project
      • dmgalpha
        ... Circular the crop-circle is around the photo only touching the corners, so you have to redo the cropping for new size. ... depending on the lens type and
        Message 3 of 3 , Apr 25, 2007
          > This is possible with Fullframe as it is set to "no crop". With
          Circular the crop-circle is around the photo only touching the
          corners, so you have to redo the cropping for new size.
          >
          > I think the fullframe is meant for corrected wide-angel , so my
          question is:
          > Does ptgui/panotools handles the remapping in different way
          depending on the lens type and does it have any impact on the final
          projection of the panorama.
          >
          > Visually I do not notice any odities.
          >


          This is a problem of PTgui. In panotools there is C and S cropping. S
          does not require reoptimization. Hugin use S cropping. PTgui uses only
          C cropping

          Technically speaking panotools/hugin treat both types of fisheye
          lenses as "Azimuthal Equidistant". BTW, not all fisheye lenses are
          created equal. There is a rare bread of "Stereographic" which are
          significantly superior, but more expensive, and I don't think there is
          a single one in the market these days. Ortographic lenses also exist,
          but are even more rare.

          If you don't specify any cropping a circular fisheye will be cropped
          automatically with a circle equal to the width of the frame as in the
          JPEG (ignoring exif rotation fields).

          dmg
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