Question for Lens Gurus and other insightful LF'ers

Discussion in 'Large Format Cameras and Accessories' started by jonw, May 20, 2006.

  1. jonw

    jonw Subscriber

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    I am always checking out barrel lens to see if they will fit a particular shutter. I just discovered that my Wollensak 9" (229mm) f5.6 raptar copy barrel lens are threaded such that they will fit a large alphax shutter I have which came with Wollensak 11 7/8" (302mm) f4.5 lens. The overall length of the 9" raptar copy lens in its barrel is 69.48mm and the overall length of these cells in the alphax shutter is 70.27mm. This appears to be a minimal difference (.79mm), but should the quality of the photographs from the cells in the barrel be equivalent to pics with these cells when using them in the more convenient alphax shutter? Now I realize this will best be checked on my V8 deardorff, but I want the local gurus to provide me with your techinal expertise and opinions. I thank you for your interest and comments.
     
  2. bdial

    bdial Subscriber

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  3. User Removed

    User Removed Guest

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    I believe the one problem you need to work out is that your new lens is a 5.6 and the shutter is marked 4.5. Your aperture scale will be wrong, so you will want to work out the math or get SK grimes to put a new F/stop scale on it for you.
     
  4. jimgalli

    jimgalli Subscriber

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    I don't have a Knowledgeable answer for you but FWIW in the case of the Computar f9 copy lenses, when the factory put them in shutters for general photo use, they added a 1mm spacer at the rear cell so the shuttered version is 1mm futher apart in the spacing than the copy version in barrel. Maybe the 229 would react the same. All you can do is test.
     
  5. df cardwell

    df cardwell Subscriber

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    How will you be using this lens ? It doesn't have excess coverage at normal working distance: plasmats and dagors are extremely sensitive to spacing. But stopping well down, and not enlarging the negatives, might obscure any problems.

    But this is all pointless speculation: it is too complex to predict what might happen. You tell US if it works !

    d
     
  6. Dan Fromm

    Dan Fromm Member

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    Jon, what you're really asking us is whether you absolutely positively have to do the job right. In other words, is the lens/shutter combination worth putting any money into?

    I'm not acquainted with the 9"/5.6 Wolly copy lens and I don't know the standards to which you work. You're going to have to ask the lens whether it is good enough for you when set up incorrectly.

    Before you do much more, if the barrel has a diaphragm, put the cells back in, hang it in front of a 35 mm SLR, and shoot it wide open and stopped all the way down (f/11? f/16) at the distances you hope to use it to assess central sharpness when the lens is set up right. That test may convince you not to go farther.