Recessed lens board

Discussion in 'Medium Format Cameras and Accessories' started by Bruce Osgood, Apr 5, 2005.

  1. Bruce Osgood

    Bruce Osgood Membership Council Council

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    Does anybody know at what point a recessed lens board becomes necessary for 4X5 press cameras? I'm considering a 90mm for my Bush Pressman and I don't think a recessed board is necessay at this size but wonder how wide I could go before it is necessary?

    Thank you,
     
  2. Bruce Osgood

    Bruce Osgood Membership Council Council

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    OOOPs, sorry - wrong catagory. Meant to put it in LARGE FORMAT.....
     
  3. Dave Parker

    Dave Parker Inactive

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    The Bush is simular to the Graphics, and I was able to use a 90mm optar on my Crown with no problem, I would think, depending on the rear element of the lens your using you should be able to use a 90mm on the Bush as well.

    Dave
     
  4. Paul Howell

    Paul Howell Member

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    It may depend on if your Bush has a focal plan shutter in the back. I have a crown and itt does not require a recessed board, but my speed with the focal plan does.

    Paul
     
  5. brimc76

    brimc76 Member

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    Bruce, I use a 90mm Super Angulon on my Crown Graphic Special with a regular, flat lensboard, but I have to switch to a recessed board when I put it on my 4x5 Arca Swiss "B" type monorail. I have heard that you can get down to a 65mm or 75mm before going to a recessed board on the Crown Graphic because there is no focal plane shutter.
     
  6. David H. Bebbington

    David H. Bebbington Inactive

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    You should be able to get a focus with your lens on a flat panel. The main question may well be where the front standard of your camera sits with the 90 mm lens at infinity focus. Older 90 mm lenses (like an Angulon) seem to have a back focus of around 90 mm as you might expect, with more modern ones (Super Angulon, Nikor SW) the back focus could well be 100 mm.

    With my Speed Graphic, I made a domed lens panel with about 20 mm extension which was great for this camera and a 90 mm Angulon, enabling the front standard to sit on the rear (wide-angle) track. This panel was, however, useless for a 90 mm Nikor SW and a Crown Graphic, since it put the standard right on the gap in the focusing track. On a flat panel, the lens sits happily on the end of the main focusing track.

    Another consideration is the size of your fingers. If you have big fingers, setting a lens in a #0 shutter in a recessed panel less than 4" square is very hard!
     
  7. AllanD

    AllanD Member

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    If you can find the spec for the lens, you can measure directly. Just put a standard lens board (without lens) on the camera. Set the front standard as close to the focal plane as it will go. Now measure the distance between the focal plane and the front of the lens board. If the distance is greater than the "flange focal distance" (100mm for the 90SA), then you need a recessed lens board. If you want movements, then you must factor in the minimum bellows extension you require.

    See http://www.schneideroptics.com/info/vintage_lens_data/large_format_lenses for lens data (presuming your not in the market for new)
     
  8. r-brian

    r-brian Member

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    I've used a 90mm Optar on a flat board on my ex-Pressman. The front standard sits right on the back edge of bed and you DO need to drop the bed or it shows up in your picture. 90m is the shortest lens you can use. The lens boards are so small that I think it would be impossible to have a recessed board.

    Brian
     
  9. Bruce Osgood

    Bruce Osgood Membership Council Council

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    Thank you Brian and everyone else who responded. I think Brian has my answer. I hadn't considered how small the lens board actually is: 3" x 3".
     
  10. mark

    mark Member

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    They are tiny aren't they.