Film holder depth for 8 X 10greenspun.com : LUSENET : Large format photography : One Thread
I'm building an 8X10 camera, and am presently putting together the ground glass back. In order to get the glass in the correct position, I need to know the correct film holder depth. Is there a standard film holder depth for 8X10? If so, what is it? Does anyone have any input on which brands of used 8X10 film holders to buy, and which to avoid? Any advice would be greatly appreciated.
-- Chris Aschoff (firstname.lastname@example.org), August 20, 1997
I don't know the correct depth, but i can say for sure that there is an ISO standard. Used holders: on the LF page there are comments about used 4x5 holders which might apply also to 8x10 holders.
-- Quang-Tuan Luong (email@example.com), August 25, 1997.
I have built several large format cameras including an 8x10. I found that an easy way to determin the proper ground glass position is to use and actual 8x10 holder for your camera's sring back plate and mount the the glass into the slot where the film normaly rests. You can find some nice wooden Graflex and Kodak holders that when striped of the paint and stained are quite nice to look at. If you can find the Graflex holder with the large metal plate at the top held to the holder with slotted screws you will find that this is easiest to take apart and put back together again after you have taken out the center plates and mounted the ground glass. I recommend that you stay away from plastic holders.
If you have questions, please feel free to Email me.
Britt Leckman Northern Virginia Community College
-- Britt Leckman (firstname.lastname@example.org), August 26, 1997.
The standard film holder depth is 0.197 inches and film is assumed to be 0.007 inches thick, so the surface of the film is 0.190 inches (4.83mm) back from the face of the film holder. This is very very close to 3/16 inch (0.1875 inches) so using a 3/16" shim might be the easiest way to get the glass at the right depth.
If you are building the back from scratch, get hold of a film holder first to get the dimensions right, especially to get the slot for the light-trap ridge correct. New 8x10 film holders are pretty expensive. Even used modern (plastic) ones are fairly pricey. Older wood ones can be cheaper but make extra sure they are in good shape, light tight, and not warped. Condition is more important than brand name.
-- Ben Weiner (email@example.com), August 27, 1997.
Ooops!!! Another question from Chris prompted me to realize that I made a dumb mistake. The 0.197" depth is for 4x5 holders, and doesn't apply to 8x10 holders. I don't know the ISO standard for those, but Chris reported a depth of 0.255" - 0.265", and when I quickly re-measured one, I got about 6.7 +/- 0.3 mm (0.26" +/- 0.01").
-- Ben Weiner (firstname.lastname@example.org), September 03, 1997.