I have a question - what sort of distortion/aberration is this?

Discussion in 'Digital Photography' started by valdore, Sep 30, 2008.

  1. valdore macrumors 65816


    Jan 9, 2007
    Kansas City, Missouri. USA
    Attached files... the second is a cropped version of the small building in the upper right. The lines of the building make it appear as though the camera moved, but it was tripod mounted. Something went awry here, and I was wondering if someone could articulate it for me.

    Attached Files:

  2. krye macrumors 68000


    Aug 21, 2007
    This is an HDR shot right? 5-7 frames? Is it possible that the camera moved ever so slightly between shots? I know it was tripod mounted but even if it moved a hair between shots, you could see something like this.
  3. ChrisA macrumors G4

    Jan 5, 2006
    Redondo Beach, California
    Simply placing the camera on a tripod does not mean the camera did not move. Did you bump the camera when you released the shutter? was the wind blowing? It is also possible the mirror when it slapped open shook the camera. What kind of tripod and was it weighted down with sand bags or water jugs?
  4. jampat macrumors 6502a

    Mar 17, 2008
    I agree, tripods are better than hand held, but if they are easy to carry, they are easy to move when you want 7 identical shots. As it appears to be just a slight shift in one image, you should be able to move that image over and perform a slight crop on the pic to avoid the small line around the edge I'd think. Pretty interesting shot. I'm not convinced I like the animation style that comes with most HDR shots, but it is really eye catching and different.
  5. dllavaneras macrumors 68000


    Feb 12, 2005
    Caracas, Venezuela
    Do you have a zoom lens?

    If you have a zoom lens, is it possible that you're experiencing from "zoom creep*"?

    * Zoom creep: When the zoom ring doesn't stay in the focal length you set it to, and it "creeps" a little, causing slight variations in the zoom.
  6. SLC Flyfishing Suspended

    SLC Flyfishing

    Nov 19, 2007
    Portland, OR
    Valdore is famous for making HDR's from a single RAW exposure. If this is the case with his photo, then I'm thinking the most likely culprit is the software he used to combine the files for the final HDR just farted or something.

  7. ChrisA macrumors G4

    Jan 5, 2006
    Redondo Beach, California
    You would be correct if there was not geometric distortion in the image. With a distorted image the image scale varies and is different on different parts of the frame. So a brick (say) is smaller if the camera is aimed directly at it and when you try and move it it does not complely cover the larger image of the same brick.

    You can solve this problem. But you have the "warp" the images together. simple shifts don't work. There is software that can do this kind of image warping and it's even free but it's not easy to use. People prefer the quick automated solutions. Or maybe it's just that few people are both great artists and great technicians.

    HDR and panoramas are really the same thing. Only the final blending at the end differs. In both cases the hard part is aligning the images and the problem becomes really hard if there is any geometric distortion involved. Photoshop can do a decent job. but look to "panotools" for the real deal. http://panotools.sourceforge.net/
    What this software does is use "control points", which are identifiable points in an image, like the corner of a window, the horizon line or the edge of a building. The software can warp the images so that corresponding control points are warped to the same place in the final image. The process is not 100% automatic.

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