This seems to be tricky territory...
I have Kodak / Folmer 5x7 sheet-film holders that appear to be post- WW-II, and are black-stained wood, with metal fittings at the dark-slide end.
I also have several 4x5 / 5x7 sheet-film holders that are in nice varnished "furniture-quality" frames.
Then there are the true plate-holders: these are usually varnished, and have the semi-circular notch. ( I am sure there were black-stained plate holders too, but plate photography seems to have declined rapidly by WW-II).
I was playing around with my Rochester Optical cameras and variety of film-holders, and did discover something: the Rochester OPTICAL Co. & Premo cameras all seem to be compatible with modern film -holders (ie: the ridge for the light-trap corresponds to the groove in the camera back). I found one 5x7 Rochester CAMERA Co. (Poco) that has this ridge in a different place, and will NOT engage the light-trap groove in the "standard" view camera back...
At some point in the 1890's, "Rochester Optical Co." and "Rochester Camera Co." combined ( and were eventually bought by Eastman), but I don't know if /when they standardized backs & film-holders between the "Premo" and "Poco" cameras...
I also have a plate-holder that holds a 5x7 plate, but the outside dimensions are too large to fit a standard 5x7 back... ?
I am somewhat dumbfounded by the prices that 5x7 film holders are fetching... quite a bit for a "dead" format (as my friends all tell me)...
I agree with you there. I think the problem is, camera manufacturers have sidelined the 5x7 format for many years, but there are a lot of photographers picking up these cameras because they like the format, but the holders have not been produced for quite some time. So if they do appear on auction sites, there are quite a lot of photographers trying to get hold of them!
Originally Posted by Luddite Frank
I have been lucky in picking up 13x18 cm, and half plate film holders, primarily because I think some owners of 5x7 cameras have not considered them as 5x7 holders. Film formats I can either get directly, or trim to size in the darkroom.
PS. Oooops, should I have really said that. Actually, on APUG people probably realise that, but I think on the big auction site, they can slip past!