please critique - is this barrel distortion bad? how to correct?

Discussion in 'Digital Photography' started by valdore, Jul 14, 2008.

  1. valdore macrumors 65816

    valdore

    Joined:
    Jan 9, 2007
    Location:
    Kansas City, Missouri. USA
    #1
    I am seeking opinion and advice on the barrel distortion in this photo resulting from using my wide angle lens (at 17 mm on a full frame sensor).

    The buildings look like they are leaning backwards, as a result of the wide angle effect. And out of curiosity, how would I correct it in Photoshop?
     

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  2. Edge100 macrumors 68000

    Joined:
    May 14, 2002
    Location:
    Where am I???
    #2
    The barrel distortion isn't an issue (I believe you use the 17-40L, yes?); I have the same lens, and even on a 5D, it's not too bad (it's a really good lens!).

    The perspective distortion can be repaired in PS. Here's a tutorial that explains it better than I could:

    http://www.kenrockwell.com/tech/correctinglensdistortion.htm
     
  3. cube macrumors G4

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    May 10, 2004
    #3
    The best tool do this is DxO, if your equipment is supported.
     
  4. ChrisA macrumors G4

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    Location:
    Redondo Beach, California
    #4
    This is NOT "barrel distortion" and is not a defect. This will happen with ANY camera when you aim it upward. The effect is greater with a wide angle lens not because the lens is wide but because you are close to the subject and therefore must aim upward at a steep angle. The simple explanation is that the top of the building as farther away from the camera than the bottom so of course being farther away it looks smaller.

    The traditional way to correct this is to use a large format camera and set the film plane vertical (camera aimed horizontal) and then shift the lens upward to shift the subject back onto the film. Small format cameras do not typically allow shifts (there are some special lenses mode just for architectural photography.) so you have two options (1) get way back and shoot from a much longer distance so the camera need not be aimed upward or "fix" the image in Photoshop. PS has a perspective control that is easy to use. But the advice from most architectural photographers is to correct out only "most" of this. If all of the vertical lines are exactly parallel then it looks un-natural, leave them a little bit convergent
     
  5. jwt macrumors 6502

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    Mar 28, 2007
    #5
    As others have stated, this image is not barrel distorted--it is keystoned. PS will fix this no problem.
     
  6. anubis macrumors 6502a

    Joined:
    Feb 7, 2003
    #6
    Actually, technically what you're referring to is not barrel distortion, nor keystone distortion. The distortion you're referring to is called the Scheimpflug condition. Even with a PERFECT lens, the only way to correct it in the camera is to have a lens that has independent movement in all axis from the focal plane (I'm betting that no one on this form has a Scheimpflug camera). Otherwise, you'll have to Photoshop it.

    [​IMG]
     
  7. John T macrumors 68020

    John T

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    Location:
    UK.
    #7
    'Fraid you've lost your bet! I still have my Father's Goertz 1/4 plate camera with rising and tilting front.
     
  8. Kebabselector macrumors 68030

    Kebabselector

    Joined:
    May 25, 2007
    Location:
    Birmingham, UK
    #8
    Does a TSE lens count :p

    (no i've not bought it yet)
     
  9. OreoCookie macrumors 68030

    Joined:
    Apr 14, 2001
    Location:
    Sendai, Japan
    #9
    No, it's not barrels distortion, it's falling lines (which I think works well on this shot). Basically the plane of the building's wall is not parallel to the focus plane and thus the building seems to `fall backwards.' It's not a fault of the lens, but a result of the way you've composed the shot; the effect is increasingly pronounced for smaller viewing angles (i. e. for wide-angle lenses).

    The only way to avoid is to get a tilt lens (expensive) or a camera which allows this (expensive). You can get rid of this effect in Photoshop to certain degrees, but I think it works rather nicely on your shot :)
     
  10. anubis macrumors 6502a

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    #10
    Damn! Alright, you win ;)
     
  11. hector macrumors regular

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    Cheltenham, UK
  12. Muncher macrumors 65816

    Muncher

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  13. bocomo macrumors 6502

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    New York
    #13

    and i have a 4x5 toyo! ha, take that! :)

    i think the "falling away" of the building fits the mood of this particular pic

    but i do question the flowers being in color. it draws the attention to them which competes with the building which i consider the main character in this pic. just a thought
     
  14. unclegit macrumors member

    Joined:
    Jan 10, 2008
    #14
    You'd bet wrong then ;)

    [​IMG]

    Also it's not a "Scheimpflug camera" - just a view/field camera.

    It's my preferred rig for landscape work ;)
     
  15. compuwar macrumors 601

    compuwar

    Joined:
    Oct 5, 2006
    Location:
    Northern/Central VA
    #15
    Canham MQC 57
    Calumet 4x5 (2x)

    Guess you haven't been reading here much, I know there are at least three or four other LF shooters here.

    :p
     

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