Reducing bloat/opposite of fish-eye lens?

Discussion in 'Photoshop' started by Boppy, Apr 6, 2007.

  1. Boppy

    Boppy Guest

    Hi, I've got a photo of a piece of artwork - tiles mounted in a wooden
    frame. It has come out looking as though it's been taken with a fish-
    eye lens.

    Obviously I could reconstruct it tile-by-tile but it would be much
    easier if I didn't have to.

    Is there an easy way to straighten it out? I've cropped it using the
    perspective option but it still bulges in the centre.

    Here is the image cropped: http://i5.tinypic.com/435a1ic.jpg

    Thanks in advance for advice.

    B
     
    Boppy, Apr 6, 2007
    #1
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  2. Boppy

    Mike Russell Guest

    Photoshop CS2 has a Lens Correction filter that will do this.
     
    Mike Russell, Apr 6, 2007
    #2
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  3. Boppy

    Boppy Guest

    Thanks Mike - sorted.
     
    Boppy, Apr 6, 2007
    #3
  4. Boppy

    Hunt Guest

    Thanks Mike, I did not know that. I've used Andromeda's LensDoc for anti-pin-
    cushion/barrel distortion. I guess like almost all of my older plug-ins, many
    find their way into PS, as some time. Old guys, such as myself, just grab for
    what they "grew up on," and do not explore all of the new filters with each
    release. I'll have to play with it in a side-by-side and see if there are
    any/many differences between the two.

    Hunt
     
    Hunt, Apr 6, 2007
    #4
  5. Boppy

    Joe Guest

    I just have the chance to look at the image and I can say that Photoshop
    (at least CS2) has quite afew option to correct lens distortion.

    - It has built-in few plug-ins for lens adjusting

    - Hmmm I don't remember all the options but I think the Skrew or free-hand
    etc. should be able to straighten the image.
     
    Joe, Apr 7, 2007
    #5
  6. Boppy

    =\(8\) Guest

    The Photoshop lens correction filter is very week. If you have a strong
    fisheye effect it will trash the image long before it corrects it. You can
    use something like Andromeda's LensDoc 3.0 or you can try the Filters >
    Distort > Spherize filter with negative amounts. I would run a test run of
    this filter to find out how much you need, then undo it and apply the amount
    in 3rds (apply 1/3 of the total amount needed three times.) I find this
    gives a smoother result than doing it all in one step.

    =(8)
     
    =\(8\), Apr 8, 2007
    #6
  7. Boppy

    Mike Guest

    Further to that - this will work pretty well in your case. To avoid distortion at the edges you need to enlarge the
    canvas (keeping your image in the centre of the canvas). Approximately doubling the width and then setting the height
    to the same (so you have a square canvas) should be enough. Then around -10% spherise should do it.

    Mike
     
    Mike, Apr 10, 2007
    #7
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