Distortion Easel

Discussion in 'Enlarging' started by cheesecrackers, Jan 4, 2011.

  1. cheesecrackers

    cheesecrackers Member

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    The popular device, by Berenice Abbott, I'm guess is no longer in production... as her company that made them died out.

    I know this effect can be mimicking by raising the paper at an angle during the exposure, but does anyone have a proper technique to this? It seems like a fun thing to experiment with.
     
  2. David A. Goldfarb

    David A. Goldfarb Moderator Staff Member Moderator

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    I usually just put quarters under the edge of the easel I want to tilt up. I also have a tilting neg stage for this purpose, which some enlargers have, and by combining easel tilt and neg tilt, you can use the Scheimpflug principle (that the neg plane, the focal plane, and the lens plane all meet in a line when they are not parallel), just like on a view camera to compensate for the change in the focal plane, when you want to correct distortion.

    The effect you can achieve this way is equivalent to rear tilt on a view camera, meaning you can correct distortion in one visual plane, so it's good for something like a flat building facade, but isn't so useful for a group of rectangular structures at various distances from the lens.

    Also, since you are focusing on the film and not the scene in three-dimensional space when enlarging, you don't have the control over the focal plane that you would with a view camera in the field, and if it's out of focus on the neg, it will be out of focus in the print.
     
  3. ic-racer

    ic-racer Member

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    You'd be surprised how much tilt is needed to correct just a slight upward camera tilt from a camera with no front rise. (Image shows actual settings; not exaggerated)

    [​IMG]
     
  4. Ronald Moravec

    Ronald Moravec Member

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    I have a setup with two boards hinged at one end. Place the easel on one board.

    Less angle is reguired if the head tilts in addition to the easel.

    Make up a focus sheet with grid lines so you can do more than eyeball parallel.

    I usually use a film strip with sprocket holes so I can focus top to bottom. Then substitute the real neg. There is no good way to use a grain focuser. The usual advice to just stop down is poor at best.

    Lastly the bottom is magnified more than the top requiring more exposure. Do a base exposure + a bottom to top burn to account for the time difference.
     
  5. 2F/2F

    2F/2F Member

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    Are you talking about altering convergence in the image, or about doing "special effects" a la Wee Gee? For the former, the pic above shows what to do. You either tilt the baseboard or shim the easel. I do the latter. I trace over the grid on some graph paper with a dark liquid ink pen and put it on the easel to help me determine how much to shim the easel. Then I tilt the lens of the enlarger to lay the plane of focus across the surface of the print. If you are talking about the Wee Gee thing, pick up his book "Wee Gee's Creative Camera" for an explanation of how he does it.
     
  6. michaelbsc

    michaelbsc Member

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    How much upward tilt on the negative?



    Where did you get that great table? I\'m going to be rebuilding my space this summer, and I have been trying to figure out how to make something like this.
     
    Last edited by a moderator: Jan 8, 2011
  7. Rick A

    Rick A Subscriber

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    I have a large package of button magnets in my DR for many purposes. One in particular is for stacking to raise an easel to correct minor convergance distortion(or create it), they dont slip like coins.
     
  8. ic-racer

    ic-racer Member

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    This is the image I made with the enlarger that day. I do have an un-corrected print, but I can't find it right now. (210mm lens on 8x10)

    The table is free with the rest of the enlarger :smile:

    Another way to look at it is that for $170 you can get a similar table on ebay and a Durst 138 comes attached to it for free. http://cgi.ebay.com/DURST-S-45-LABO...403?pt=LH_DefaultDomain_0&hash=item2eb1fa8ecb
    [​IMG]
     
    Last edited by a moderator: Jan 8, 2011
  9. michaelbsc

    michaelbsc Member

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    And you will hold it for me until I can get enough elves together to bring it from NM? :wink: