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#1
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Spare parts for Crown Graphic camera
As to your first question re a ground glass, there have been plenty of threads
by people who are making their own ground glass and polishing it down to a more fine degree than the commercially available ones. I believe that there is a lot of material on this at photo.net. argon |
#2
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Spare parts for Crown Graphic camera
As to your first question re a ground glass, the first thing is to clean it. Remove it
from the camera, and use mild soap and water. |
#3
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Spare parts for Crown Graphic camera
As to your first question re a ground glass, the first thing is to clean
it. Remove it from the camera, and use mild soap and water. Agreed. One more thing to watch for upon disassembly is a fresnel lens + ground glass combination. Because the fresnel is likely cast from acrylic, it is very soft. Be careful not to damage the grooves. When resassembling a Graflex camera that has a fresnel, the fresnel should be placed on the lens side of the ground glass with its grooved surface in contact with the ground glass surface. If the fresnel is removed from a camera that previously had one installed, there will be a focus error introduced. The error is a sum of the displacement of the ground glass by the thickness of the missing fresnel plus a focus shift caused by refraction of off-axis light by the fresnel lens. Graflex cameras having fresnel lenses were configured to move the gound glass away from the lens by a distance about 1/3 the thickness of the fresnel lens to accomodate the rearward focus shift. (Source: What the Camera Technician Should Know about Fresnel Screens, J. M. Harris, The Camera Craftsman, July/Aug--Sept/Oct 1980) Because some fresnels are replaced with thicker or thinner units, running some careful focus tests would be wise after you reassemble the camera. Bill Schneider |
#4
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Spare parts for Crown Graphic camera
"Serge Korolev" wrote in message m... Hello, I've been lucky to pick-up one of the late Crown Graphic Special models a few months ago and, though I am quite satisfied with the camera, I would have some things improved: 1) The ground grass' surface is not evenly coated in sense that it punctured with a lot of small transparent spots. And its coated part seems a bit old dirty. All this makes it quite difficult to focus even at infinity. I've been thinking to replace it with a new one but I am not sure if I suppose to look for this particular model's groud glass (framed in a Grafloc holder) or those sizes are standardized. 2) The camera rails used to be a bit tough on movements and I think I figured the source of this disturbance - small back rails (those which are sliding under the guides) are not perfectly flat. The camera doesn't look to have any complicated mechanics and so I believe it should not be hard to disassembe it.. Would it be possible to straighten the rails to the working condition or I've better look for a spare part? Do any sources of the parts for Graflex still exist? I'd buy another Copal #0 lens board as well but I don't know if the only place to hunt it is eBay. I am in Europe (Italy) and so local sources of those items would be preferable.. Though I have a number of friends in the US who could buy and ship goods to me with no problem. Thanks, Serge PS. If you answer to email please replace "usenet" part of it with "serge". Unfortunately, the best source of parts (and service) is no longer available. This was Fred Lustig, but Fred suffered a stroke some time ago and I think is still out of action. However, I think you can fix the back without much trouble. The Crown Graphic Special is a fairly late version of the camera. The "special" part is that it came with a Schneider Xenar in Compur shutter rather than the Rodenstock or Wollensak lenses generally supplied. It will have a Graflok back. The Graflok back has both a ground glass and a fresnel lens. The fresnel lens is under the ground glass with the grooves facing the ground side of the glass. They are held in place by clips facing toward you when looking at the ground glass. Slip the ground glass panel out of the camera and remove the ground glass and fresnel by unscrewing the clips. Wash both in dishwashing detergent and luke warm water. If necessary rub the surfaces very gently with a soft cloth. Rinse well and blot dry with paper towels. If there is something like glue on the ground glass it can be cleaned with a solvent like Alcohol or Acetone with no damage. The fresnel lens should NOT be cleaned with anything other than detergent and water or window cleaner, even alcohol may injure the plastic. Re-install the way the sheets came out. That should brighten up the image considerably. Somtimes the fresnel lens is missing. I don't know a ready source of replacments. It is necessary to have the fresnel there because the ground glass will be the wrong distance from the focal plane otherwise. The focus rails can be lubricated by wiping them with synthetic grease. If they are not lined up its possible the bed braces are not aligned correctly or the bed has been warped. All Graphic cameras are pretty rugged and are usually repairable. There are reprint factory instruction books available from John S. Craig at http://www.craigcamera.com and from Petra Keller at: http://www.camerabooks.com Not too expensive, both are very reliable dealers. A good source of general information on Graflex made cameras is at: http://www.graflex.org -- --- Richard Knoppow Los Angeles, CA, USA -- --- Richard Knoppow Los Angeles, CA, USA |
#5
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Spare parts for Crown Graphic camera
"Serge Korolev" wrote in message m... Hello, I've been lucky to pick-up one of the late Crown Graphic Special models a few months ago and, though I am quite satisfied with the camera, I would have some things improved: 1) The ground grass' surface is not evenly coated in sense that it punctured with a lot of small transparent spots. And its coated part seems a bit old dirty. All this makes it quite difficult to focus even at infinity. I've been thinking to replace it with a new one but I am not sure if I suppose to look for this particular model's groud glass (framed in a Grafloc holder) or those sizes are standardized. 2) The camera rails used to be a bit tough on movements and I think I figured the source of this disturbance - small back rails (those which are sliding under the guides) are not perfectly flat. The camera doesn't look to have any complicated mechanics and so I believe it should not be hard to disassembe it.. Would it be possible to straighten the rails to the working condition or I've better look for a spare part? Do any sources of the parts for Graflex still exist? I'd buy another Copal #0 lens board as well but I don't know if the only place to hunt it is eBay. I am in Europe (Italy) and so local sources of those items would be preferable.. Though I have a number of friends in the US who could buy and ship goods to me with no problem. Thanks, Serge PS. If you answer to email please replace "usenet" part of it with "serge". Unfortunately, the best source of parts (and service) is no longer available. This was Fred Lustig, but Fred suffered a stroke some time ago and I think is still out of action. However, I think you can fix the back without much trouble. The Crown Graphic Special is a fairly late version of the camera. The "special" part is that it came with a Schneider Xenar in Compur shutter rather than the Rodenstock or Wollensak lenses generally supplied. It will have a Graflok back. The Graflok back has both a ground glass and a fresnel lens. The fresnel lens is under the ground glass with the grooves facing the ground side of the glass. They are held in place by clips facing toward you when looking at the ground glass. Slip the ground glass panel out of the camera and remove the ground glass and fresnel by unscrewing the clips. Wash both in dishwashing detergent and luke warm water. If necessary rub the surfaces very gently with a soft cloth. Rinse well and blot dry with paper towels. If there is something like glue on the ground glass it can be cleaned with a solvent like Alcohol or Acetone with no damage. The fresnel lens should NOT be cleaned with anything other than detergent and water or window cleaner, even alcohol may injure the plastic. Re-install the way the sheets came out. That should brighten up the image considerably. Somtimes the fresnel lens is missing. I don't know a ready source of replacments. It is necessary to have the fresnel there because the ground glass will be the wrong distance from the focal plane otherwise. The focus rails can be lubricated by wiping them with synthetic grease. If they are not lined up its possible the bed braces are not aligned correctly or the bed has been warped. All Graphic cameras are pretty rugged and are usually repairable. There are reprint factory instruction books available from John S. Craig at http://www.craigcamera.com and from Petra Keller at: http://www.camerabooks.com Not too expensive, both are very reliable dealers. A good source of general information on Graflex made cameras is at: http://www.graflex.org -- --- Richard Knoppow Los Angeles, CA, USA -- --- Richard Knoppow Los Angeles, CA, USA |
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