How do I correct converging verticals ?

Discussion in 'Digital Cameras' started by Barry Smith, Dec 9, 2003.

  1. Barry Smith

    Barry Smith Guest

    Not specifically a digital question, but this is the only
    photo group I subscribe to. If there's a more suitable group
    to ask in please let me know.

    I have an image, scanned from a 35mm slide, with converging verticals.

    How can I correct this ?
    1. Taking the photo again is not an option.
    2. I do have a slide projector if one solution is to project onto an
    angled screen and photograph the image (could I get all the projected
    image in focus this way?)
    3. A software solution would be nice !
    4. A professional solution (if there are labs in the UK that could do this)
    to obtain one A4 sized print is aceptable, if not too expensive.

    Hoping someone can offer advice.

    Barry Smith, Dec 9, 2003
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  2. Barry Smith

    wes Guest

    If you do have Photoshop, you can use the free transform tool to straighten
    the church. Just make a duplicate of the background, hit Ctrl + T, hold the
    Ctrl and Shift keys down and drag the upper right corner to the right. ( For
    information, the Ctrl lets you choose the upper right corner and the Shift
    allows you drag in a straight line.
    wes, Dec 9, 2003
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  3. Barry Smith

    PhotoMan Guest

    See the other replies about P Shop. Also, I'd apply a little CW rotation
    *before* doing the perspective correction.
    Joe Arnold
    PhotoMan, Dec 10, 2003
  4. Barry Smith

    Don Stauffer Guest

    Many editors feature this. I use PSP which does a good job with this.
    Don Stauffer, Dec 10, 2003
  5. Barry Smith

    Barry Smith Guest

    In message <>
    It's very kind of you to offer, but I hope you don't mind if I
    say I'd rather do it myself.

    The first point being that scanned from a slide it's a rather large file
    (about 18Mb).

    I supose my main question should have been - can this be done relatively
    easily in software.

    However, if I do struggle, and you don't mind downloading 18Mb, I
    might take you up on the offer.

    Barry Smith, Dec 10, 2003
  6. Barry Smith

    Barry Smith Guest

    In message <>


    Thanks for all the replies. I prefer not to use a PC if I can
    help it - my preferred OS is RISCOS. There is photo editing
    software available for it so I'll ask if it has the same features
    as Photoshop/Paintshop. My guess is that it will.

    Up until now all I've needed to do with photos is resize and adjust
    the gama, colour etc. so I've not bought any software for this sort
    of job.

    I had a suspicion that I would get replies saying that although
    it could be done, the results would be poor (jagged straight lines?)
    and that an 'optical' solution would be needed.

    Now you've all put my mind at rest I'll have a go with software.

    Many thanks

    Barry Smith, Dec 10, 2003
  7. Barry Smith

    Barry Smith Guest

    In message <>
    I guess those would be quite expensive. I've never actually seen one
    but read about them many years ago. I would imagine there's a very
    limited market for them, especially now, if software can now do the job
    almost as well.

    Barry Smith, Dec 10, 2003
  8. Barry Smith

    Crash Guest

    I agree with Marvin. The first thing that has to be done to this image is a
    bit of rotation. Then a simple crop with perspective correction (in
    Photoshop) and you can take out the perspective effect. You realize that
    will have to lose some of the current image when you do a perspective
    correction - unless you don't mind ending up with a non-rectangular image.
    Crash, Dec 11, 2003
  9. Barry Smith

    Mark Johnson Guest

    But that's the point - it can't. If you have no more light, no more
    image, to drag in, or you're interpolating pixels to push out, you're
    either introducing artifacts or you're dragging in flat background
    color. Would be far better to use a PC lens at the scene. I'm sure
    they are available, used. Whether they could be adapted to any
    particular body, that I don't know.
    Mark Johnson, Dec 11, 2003
  10. Barry Smith

    Barry Smith Guest

    In message <[email protected]_s52>
    Well the original has been cropped slightly (especially the bottom
    and right-hand side) to give what you see on my website, so I think
    losing some of the image may not be a problem.

    Hopefully Father Christmas will bring me some software :)

    Barry Smith, Dec 12, 2003
  11. Barry Smith

    Barry Smith Guest

    In message <>
    Just doing a bit of Googling...
    Loreo Products - LOREO Perspective Control (PC) Lens in a Cap

    Looks interesting, but at $21 I don't think the quality will be great.

    Barry Smith, Dec 12, 2003
  12. Barry Smith

    Mark Johnson Guest

    Might work pretty good for $20. It's got a 42mm thread though.
    Mark Johnson, Dec 12, 2003
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