Non"0" groundglass

[Neal Shields]

In another post Bob Solomon refers to the fact that "a IV it has a non "0" groun dglass position".

I would assume all ground glasses are set to coincide with the film plane when t he holder is inserted?

What does this mean??

Neal

[Wayne_6692]

I would hope that he means that the "0" (film/groundglass position)is not in the same location (referenced to?) from camera to camera. This would be the reason why cams are not usable on different cameras, they not only have to be matched to the lens but the camera also. The V established a common "0" for all cameras (within manufacturing tolerances) so a lens with it's cam (when cut for a model V) could be used on any camera (model V). I would expect that the reason is that the groundglass was shimmed by hand for each individual camera (much the way watchmakers used to hand file gears for proper meshing) in the IV, and better manufacturing controls eliminated the need in the V. Just a guess. Where's Bob?

[Bob Salomon]

Correct.

III and IV's have non zeroed GG and thus the cams are cut for each camera and lens by serial number and are not interchangeable between cameras.

V abnd Master 45 Technikas have zeroed GG and cams are interchangeable between them as long as they are used with the lens they were cut for.

III and IV cams will not couple properly on V and later models.