Destorting a picture

Discussion in 'Photoshop Tutorials' started by paulotuatail, Feb 22, 2013.

  1. paulotuatail

    paulotuatail Guest

    Hi I am still using Photoshop 7 but I am looking into CS5.5 or 6

    I want to be able to distort a picture to rectify a distortion. What I meanis that in York (UK) we have a cathedral York Minster. To get a proper photograph to have to get close because of surrounding trees. Problem is it isa huge building so the camera has to be pointed up at an angle. This will cause the picture to be distorted. If I could rectify the pictur in Photoshop I could get the picture I want.

    Any ideas on this please.

    I do know that you can buy expensive cameras that can slide the lens upwards or downward to take the potograph but these are very rare and expensive.

    TIA

    Desmond.
     
    paulotuatail, Feb 22, 2013
    #1
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  2. paulotuatail

    one Guest

    I assume the distortion you're referring to is converging verticals. If so,
    here's a simple tutorial (not mine) for Photoshop 7 which may help:

    http://www.crhfoto.co.uk/crh/convergingverticals.htm
     
    one, Feb 22, 2013
    #2
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  3. paulotuatail

    Savageduck Guest

    What camera/lens combination are you using?

    First there is no CS5.5, that was part of the creative suite for
    specifically for creating graphics for use on mobile devices.

    So if you have access to CS4, CS5, or CS6 they have the "Lens
    Correction" filter which will allow you to correct using a camera/lens
    profile, or manually correct for vertical or horizontal distortion. If
    you shoot RAW the same corrections are available in Adobe Camera RAW or
    ACR which is integral to the CS software.

    Typical for shots of tall buildings is a base wider than the top, and
    if you are taking the shot with the intent to fix it in software, make
    sure that you leave yourself a reasonable amount of room around your
    subject building (or any other subject) as there will be some cropping
    to the original.

    The first thing to do in the "Lens Correction" filter is to straighten
    or level the building. Typically with a tall building use the
    straighten tool by taking a line from the bottom center to the top
    center of the structure. This should straighten it in the frame.

    If you have grid lines active you should now be able to see any
    "barrel" or "pin cushion" distortion imparted by the lens you are using
    and you should correct for that approximately by checking against the
    grid lines.

    Next, go to "custom" and adjust the vertical distortion appropriately.
    Don't over do this, remember your eye/camera position is just that, and
    if you were viewing from that level you would experience some
    "vanishing point" perspective effect. Your camera is not at some
    phantom point midway between the top and bottom of the building. Even
    with a "tilt-shift" lens you would not be able to full compensate for
    camera position.

    Once you have made that vertical distortion adjustment, if you wer not
    square to the building when you shot check the horizontal distortion.

    Finally, recheck the "pincushion" and "barrel" distortion correction,
    and apply the filter.
     
    Savageduck, Feb 22, 2013
    #3
  4. paulotuatail

    paulotuatail Guest

    I have a basic Sony Alpha and I have a 16-70mm lens (Lager lenses also) I can only go down to 18 as the picture starts to distort I would have to get 25 feet (ish) from it so would have to point the camera upwards. Can't afford fish eye but that distorts anyway.. Would Photoshop 7 work or not?
     
    paulotuatail, Feb 23, 2013
    #4
  5. paulotuatail

    paulotuatail Guest

    I have access to CS5.5 but can't understand why this does not have Lens Correction but CS4,5 and 6 does. Crazy :(
     
    paulotuatail, Feb 23, 2013
    #5
  6. paulotuatail

    paulotuatail Guest

    Sorry Sony Alpha 200. Must get this info right. Too early in the morning.
     
    paulotuatail, Feb 23, 2013
    #6
  7. paulotuatail

    Savageduck Guest

    PS-7 does not have the "Lens Correction" filter.

    OK. I got that you are using a Sony Alpha 200 with a 16-70mm lens, 16mm
    being the widest focal length you have available. Shooting a tall
    building from approximately 25 feet seems way too close to me. You
    would definitely be aiming at an acute upward angle. As I am not
    familiar with the location and the building you are trying to shoot,
    all I can suggest is to select an optimal vantage point further away,
    but I realize that might not be possible. So shooting as wide as
    possible, and correction any distortion with CS4/5/6 might be your only
    option.
    You can refer to my prior response for the workflow I might use with
    the "Lens Correction" filter. As always your mileage might vary.
    CS5.5 is not Photoshop, or even part of Photoshop. It is part of the
    Creative Suite and is intended as an update for Adobe "Indesign CS5"
    specifically for graphics design for mobile devices.

    There is no Photoshop CS5.5.

    It would also help if we had a visual idea of you problem, so that
    those of us familiar with making distortion corrections with PS could
    see if that would be a workable solution.
    So if you use Dropbox or any other method of sharing your images you
    could post a link to one of your problematic image captures like this.
    < https://dl.dropbox.com/u/1295663/FileChute/screenshot_132.jpg >
     
    Savageduck, Feb 23, 2013
    #7
  8. paulotuatail

    Savageduck Guest

    Never mind. I checked on your seeing exactly what you are dealing with,
    and Google was able to provide a batch of images:
    <
    http://www.google.com/search?q=york...iQKci4DQDQ&ved=0CAoQ_AUoAQ&biw=1845&bih=951or
    < http://tinyurl.com/ac5safb >

    ....and from what I can see, your problem is a case of, location,
    location, location.
     
    Savageduck, Feb 23, 2013
    #8
  9. paulotuatail

    Savageduck Guest

    ....and even the best of those needed some straightening and vertical
    distortion tweaks.
    < https://dl.dropbox.com/u/1295663/FileChute/screenshot_133.jpg >
     
    Savageduck, Feb 23, 2013
    #9
  10. paulotuatail

    Savageduck Guest

    Savageduck, Feb 23, 2013
    #10
  11. paulotuatail

    one Guest

    Savageduck quacks much sense and I would only add that how fussy you have to
    be depends on what your photograph is for. If it will end up as a relatively
    small jpeg on a web site then tweaking should be adequate; if it's going to
    be published in a glossy magazine then hiring an architectural camera/lens
    and reshooting might be necessary.

    Here's my take on more or less eliminating the converging verticals on a
    screen grab from Street View. It only took two minutes to do and is by no
    means perfect but I'd be happy to put it on a web site.

    https://www.dropbox.com/s/gfo07har1yf0paz/yorkminster.jpg

    And, finally, it's some years since I visited York Minster but it is a very
    impressive building - more than 20 storeys high. It's scarcely believable
    that it was built in the 14th/15th centuries (no hard hats then).
     
    one, Feb 23, 2013
    #11
  12. paulotuatail

    Wilfried Guest

    Hello!

    I have a different suggestion (which I already applied several times).

    Make a panorama photo:

    Set the camera at medium focal length and shoot a series of pictures
    overlapping each other so that the entire building and enough space
    around is captured. Pay attention to only _turn_ the camera from one
    picture to the next, _do_not_move_ the camera horizontally or
    vertically.

    Install a panorama photo software - I use http://hugin.sourceforge.net
    which is open source and free.

    hugin can automagically detect horizontal and vertical lines and make a
    decent "distortion" to get them right.

    hope that helps
     
    Wilfried, Feb 25, 2013
    #12
  13. paulotuatail

    Savageduck Guest

    ....and how are you going to achieve turning the camera without moving
    it horizontally or vertically?

    Keeping the camera on an even plain, either horizontally or vertically,
    is a different issue. Consider having the camera tripod mounted
    (preferably on a pano-head) now the camera can be rotated around a
    fixed point, either horizontally or vertically.
    Only if the overlaid mosaic images are a match for one of the stitching
    algorithms provided by the software.
    Even with decent software a pano of a tall structure would be tough to
    produce without stepped distortion using the technique you outlined.
    Consider, your camera would be at eye, or tripod level above ground.
    Your capture of each shot for your panorama would be from top to
    bottom, or bottom to top. This gives you a displaced point of rotation.
    To create a good "vertical" pano your ideal shooting vantage point
    would need to be at a point midway between ground level and the top of
    the building. In the case of the structure at York Minster, the Western
    front is 196ft/60M tall, so find a position about 98ft/30M above the
    ground to shoot your vertical pano. Then you should be able to stitch
    the pano with Hugin, or Photoshop, or any other pano software, and get
    a decent distortion correction.

    The real solution here is to use a "tilt-shift" lens, or a wide angle
    and fix any lens distortion in post.
     
    Savageduck, Feb 25, 2013
    #13
  14. paulotuatail

    Wilfried Guest

    You don't beleave me?
    Here http://www.awh-ew.de/images/static/IMGP0562.JPG is a picture I made
    standing on the ground level at the side of the church. From there I
    made a series of 6 pictures (free-hand) and stitched them with hugin.
     
    Wilfried, Feb 25, 2013
    #14
  15. paulotuatail

    Savageduck Guest

    You sure did a questionable job of fixing the distortion generated by
    your pano for the top of the tower and the clock face.
    This is not what is needed when shooting tall buildings. Squashing the
    tower and introducing a very obvious kink, twist, and lean is not in my
    opinion acceptable.

    BTW: What happened to the top of the tower? This is supposed to be
    trying to find a solution to capture a tall building, minimizing
    distortion, not capturing the side of a building and distorting the
    tall structures of that building, including decapitating it.
     
    Savageduck, Feb 26, 2013
    #15
  16. paulotuatail

    Wilfried Guest

    I accidently missed to take another row of pictures high enough to
    capture the top.
     
    Wilfried, Feb 26, 2013
    #16
  17. paulotuatail

    paulotuatail Guest

    Hi been a long time sinc I got back to this. There have been some interesting links one from two.three

    York Minster facts
    Length - 525 feet (160 meters)
    Width - 249 feet (76 meters)
    Height to vault - 88.5 feet (27 meters)
    West towers - Nearly 184 feet each (56 meters)
    Lantern tower - 233 feet (71 meters)
    Pictue of church
    http://www.photographers-resource.co.uk/A_heritage/Abbeys/LG/York_Minster.htm

    As you can see not an easy one to take in a built up city.
     
    paulotuatail, Mar 7, 2013
    #17
  18. paulotuatail

    paulotuatail Guest

    Yes Duncan place is good if someone will chop all the trees down. I have to get past the trees which will make it a close shot or wait untill winter when there are no leaves on the trees. PS7 does have it. I folowed the tutorial o.. gave and it worked

    Wilfried

    Can't see how taking muli pictures woluld work. I have to use a spirit level to make sure the angle is the same moving the camera around would also cause a horizontal distortion also I think.
     
    paulotuatail, Mar 21, 2013
    #18
  19. paulotuatail

    paulotuatail Guest

    Wanted to put up 3 images of my fist attempt. Only options [Post] [Discard] Image upload not available. Strange :(
     
    paulotuatail, Mar 21, 2013
    #19
  20. paulotuatail

    Savageduck Guest

    How are you attempting to post images?
    Are you using an image hosting site such as Flickr, or are you using a
    "Cloud" service such as Dropbox or G-Drive?

    If you are trying to upload a binary image file to this NG, understand
    that comp.graphics.apps.photoshop is not a binaries group.
     
    Savageduck, Mar 21, 2013
    #20
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