Posted by Les Newcomer on October 14, 2000 at 18:26:10:
In Reply to: Focus problem on Century Graphic posted by Dennis Lee on October 14, 2000 at 15:07:14:
The ground gl a s s is in the proper place. I would check
and see how firmly the back insert is sitting in
the back, I've had a back that had a weak spring (big flat thing)
that allowed the insert to drift away from the film plane. A worn
clasp can do the same thing.
the only way I've been able to check the difference between the ground gl a s s plane and the roll back plane is with the aid of some machinist's tools-a depth micrometer and some parallels.
I put the back on its back and lay the parallels on top of it
(parallels are nothing more than long square pieces of steel ground
flat and smooth) This gives the depth micrometer a reference plane
to work with.
I measure the depth to the ground gla s s on several spots, then
repeat the procedure with the roll back in place with some scrap
film and paper taped to the pressure plate.