I am hoping this is the correct forum for this issue.

I restored a Seneca 4x5 view camera with a date stamp of 1909. Over the last year or so I have been using it mostly as a pin hole camera. However, when i use it with my 127 mm or 163 mm lens the images just did not seem quite as sharp as they should be.

Let's suffice to say it has been a steep learning curve. But among the many articles I have read was the suggestion to check the distance from the lens board to the film and glass planes.

A a quick check with ruler indicated the film was about 1/8" farther back than the frosted glass. Careful measurements with digital calipers shows the film plane of the film holder is .138" (3.5 mm) farther back than the distance to the frosted glass. The film thickness is .007" (.178 mm). I check a few of my film holders and the distance is consistent.

My solution is to slide a .130" (3.30 mm) thick square frame into the film holder slot to move the frosted glass back to the film plane. This seems like a crude but effective solution but I was wondering how other folks have solved this problem.