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Thread: Perspective Correction and Edge Extension

  1. #1
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    Default Perspective Correction and Edge Extension

    Hi Mater Sifus, Gurus out there,

    Could someone kindly teach me how to best do lens perspective correction followed by edge extension. I have tried a very simple workflow in CS4 but the result was awful

    Photoshop- filter-distort-lens correction- vertical perspective- edge
    The followings are the examples

    Without correction,


    With correction but without cropping


    With correction and cropping


    Many thanks in advance...
    I will start taking pictures from now on :-)

  2. #2
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    Default Re: Perspective Correction and Edge Extension

    Any sifu
    I will start taking pictures from now on :-)

  3. #3

    Default Re: Perspective Correction and Edge Extension

    You can't stretch the edges as you tried in your second image. In some cases you can clone to extend the sides of the image; depends on the content.

    In this case, crop as you've done in your third image.

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    Default Re: Perspective Correction and Edge Extension

    Quote Originally Posted by Peano View Post
    You can't stretch the edges as you tried in your second image. In some cases you can clone to extend the sides of the image; depends on the content.

    In this case, crop as you've done in your third image.
    Thanks David.. I now realize that cropping is the only way to do or avoid tilting in the first place if possible by using long tripod and live view
    I will start taking pictures from now on :-)

  5. #5
    Member zk-diq's Avatar
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    Default Re: Perspective Correction and Edge Extension

    Perspective correction is what you are asking.
    There is a simple way to resolve, level your camera.
    Or Use a PC Lens, shift and tilt with the lens to correct your perspective.
    Using software you will reduce the quality of the image.

  6. #6

    Default Re: Perspective Correction and Edge Extension

    Quote Originally Posted by Joelhlaing View Post
    Thanks David.. I now realize that cropping is the only way to do or avoid tilting in the first place if possible by using long tripod and live view
    yes.

    and having a firm grounding in the basics of architectural photography will go a long way.

    in the end, it is just playing with 3 things, barrel distortion, if any; vertical perspective and horizontal perspective. two of the three concepts are similar.

  7. #7
    Senior Member Diavonex's Avatar
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    Default Re: Perspective Correction and Edge Extension

    Make sure you allow for more space on the left and right of picture if you need to do perspective correction otherwise some of the image will disappear during the process.

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    Default Re: Perspective Correction and Edge Extension

    just do a couple of proper shots, pano stitch them and cropped away the unwanted areas.

  9. #9
    Senior Member Diavonex's Avatar
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    Default Re: Perspective Correction and Edge Extension

    Pano stitch will not correct the perspective problem of tall buildings unless you are shooting from an elevated position.

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    Default Re: Perspective Correction and Edge Extension

    you are not making any sense. any shot from that angle would need perspective correction.

    then do
    1) couple of proper shots,
    2) pano stitch them,
    3) perspective correction on them
    4) and cropped away the unwanted areas.

    You want even more proper way then getting TS is the only way.
    Last edited by NMSS_2; 4th June 2010 at 02:17 PM.

  11. #11
    Senior Member wildcat's Avatar
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    Default Re: Perspective Correction and Edge Extension

    Quote Originally Posted by NMSS_2 View Post
    you are not making any sense. any shot from that angle would need perspective correction.

    then do
    1) couple of proper shots,
    2) pano stitch them,
    3) perspective correction on them
    4) and cropped away the unwanted areas.

    You want even more proper way then getting TS is the only way.
    Pardon my ignorance as I seldom do pano, but wouldn't stitching a couple of perspective uncorrect photos in step 2 be err... problematic for the stitching software? It may be that in one picture it is angled to the left, another it is straight and a third picture having it angled to the right?

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    Default Re: Perspective Correction and Edge Extension

    Quote Originally Posted by wildcat View Post
    Pardon my ignorance as I seldom do pano, but wouldn't stitching a couple of perspective uncorrect photos in step 2 be err... problematic for the stitching software? It may be that in one picture it is angled to the left, another it is straight and a third picture having it angled to the right?
    1) understanding your pano software and its limitation. Some so good (advanced) that anyhow shoot also can stitch, some need more "proper shots" to know where to stitch. So know how your pano software function might help in this.

    For example: if i know the software would take cue from something distinct like the horizon, i would shoot every shot with horizon in the middle of every frame.

    2) understanding your lenses and its focal length. Try figuring out the widest focal length that allows more tolerable results with your pano software. Getting some better wide lenses (rectilinear) might help, tilt shift lenses is still the easiest option.

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