Clipped Corners on Ground Glass

Discussion in 'Large Format' started by john_mcdonald, Aug 17, 2002.

  1. I am considering altering the back of my 8x10 Ansco so that it
    can take a full rectangle of ground glass, rather than needing a
    glass with all 4 corners clipped back about 1". Many big cameras
    seem to accept a full sheet of glass, without the need for clipped
    corners. I am guessing that the Ansco clipped its glass corners
    to prevent blowing out the bellows, lens, or ground glass itself
    upon rapid compression of the bellows. I would rather look at a
    full screen of glass, unless I am overlooking some potential
    problems I would be creating. Thank you in advance for your
    comments.
     
  2. The main reason for the clipped corners is to facilitate checking for vignetting. It is easier to see if the corners are obstructed by limited lens coverage or the lens shade with the corners cut out as opposed to seeing through the ground glass. You can certainly live without them if that capability is not important.
     
  3. I actually went to the trouble to clip the corners on the GG of one
    of my camera backs for the reason Dave indicated! It just shows
    to go you.
     
  4. The reason the corners are clipped is because of the large volume of air inside the large bellows. When you move the front standard forward, or backward, it is easy to break the thin ground glass with the pressure/vaccum created. It would also blow up or suck down the bellows. The clipping allows the air to escape, or draw as needed.

    Think about it!

    www.doncameron.com
     
  5. Thanks, all. Perhaps a compromise is in order. Looking carefully
    at the Ansco's back, I see that it only requires the glass to be
    clipped back about 1/2" at the corners. The current screen is
    clipped back 1". Perhaps the replacement glass should be
    clipped just enough to fit easily. Thanks to your answers, I now
    know better what the clipped corners are for. I appreciate your
    help.
     
  6. John, Clipped corners are usefull, but certainly not neccesary, as others have stated. As far as problems from air compressing by, or being sucked in by your bellows and causing damage I think that would be an issue only if your camera was fairly airtight---consider the gaps around the lensboard, the back, and the ground glass holder. Theres lots of places for air to leak but it can still be an issue if the fit is "tight." Remember trying to close the door on a VW Beetle with the windows rolled up? I think Ansel Adams mentioned the practice of having small holes drilled in the GG corners to deal with that issue should the clipped corners be too much of a distraction. I think it was in The Camera by Ansel Adams. Might be worth looking up(the 8x10 Ansco was one of his favorites, by the way) Then again, I could be wrong. Cheers!
     
  7. I have recently bought, and really like, a new Silvestri 5x loupe with a triangular swivel base that allows you to get right into the corners of the ground glass. The best loupe I have ever used.
     
  8. There is a new and excellent loupe by Silvestri with a swiveling triangular base that allows you to get right into the corners. A great innovation.
     

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