A&P Question about straight lines bending in pictures

Discussion in 'Lifestyle' started by GlobeGuy, Sep 1, 2004.

  1. GlobeGuy

    GlobeGuy New Member

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    What do you call it when straight lines bend in pictures (most prominent on buildings)? I could search more on it, if I knew what it's called. :eek3:

    And is there any tool to fix such pictures?


    Thanks in advance guys
     
  2. Jcolman

    Jcolman OT Supporter

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    I've always called it "vertical distortion". It's caused when using wide angle lenses and tilting the camera. Some lenses like fisheye lenses suffer from "barrel distortion" which caused the verticle lines to bend at the top and bottom of the frame.

    To correct vertical distortion you must use a special lens with a movable front element or move farther away and use a longer lens.
     
  3. ShackleMeNot

    ShackleMeNot MINDSET

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    You can also use photoshop to skew the buildings back to straight. Not as good as the hardware solution Jcolman listed but it's normally a cheaper option.
     
  4. GlobeGuy

    GlobeGuy New Member

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    Thank you both. :)

    How would I fix barrell distortion that occurs on a painting and its frame? This time it's on all 4 sides.
     
  5. Jcolman

    Jcolman OT Supporter

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    I assume that you're referring to a pic of a painting and frame. The only fix is to reshoot it. Use a 50mm or longer lens and make sure the camera is level.
     
  6. redna

    redna New Member

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    upload it, I bet i can fix it in photoshop. I jsut had to do this for a picture i shot of a band
     
  7. GlobeGuy

    GlobeGuy New Member

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    Thank you so much for the offer, can you tell me the steps afterward? I have quite a bit of these to fix. :)



    [​IMG]
     
  8. redna

    redna New Member

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    hmm, you could probably fix that with the spherize filter

    Filter> Distort> Spherize

    Worth a try. I'll post later with my results.
     
  9. redna

    redna New Member

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  10. redna

    redna New Member

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    This was done in about 2 minutes with a simple technique.

    First i leveled the frame with the measure tool and Image >Rotate Canvas> Arbitrary (it should be defaulted to the right degree)

    Then I duplicated teh layer

    I took the top layer and adjusted it via Free transform > Perspective

    Then I added a layer mask and took out the bottom half with a gradient

    Then I corrected the bottom the same way. I had to adjust it a little using Free Transfor> Skew as well but it lined up great.

    Thats a fairly quick improvement, I could get it much better but it would take me about 20 minutes im guessing to maintain the sharpness and get a perfect straight edge.
     
  11. redna

    redna New Member

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  12. GlobeGuy

    GlobeGuy New Member

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    You are an excellent help redna, thank you. I will get started on reading these. :)
     
  13. Jcolman

    Jcolman OT Supporter

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    I also didn't realize that photoshop could be used to correct perspective. Thanks for the info.
     
  14. redna

    redna New Member

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