Alley in Pisa, Italy

by Lars Kotthoff

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I have a Busch-Pressman Model D 4x5 camera (1940's I think) with a synchronized Meyer-Opticraft Rangefinder. I have been trying to fine tune the rangefinder in order to make it useable, but there is one problem I haven't managed to solve:

The secondary ghost image I see through the rangefinder moves vertically as I adjust the focus (and is vertically aligned with the main image when in focus), but the two images are slightly off horizontally.

This issue makes it a bit of a headache to focus, because the images are never truly aligned. Is this how these rangefinders are supposed to work? Has anyone run into this problem before?

Any advice, much appreciated! I'm not afraid of disassembling :)

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+1: I really appreciate such questions, even if I'll never have such a camera... –  Francesco Sep 6 '12 at 12:23
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up vote 8 down vote accepted

The images should be aligned horizontally. It's difficult to imagine the rangefinder mechanism becoming misaligned yet remain working, and the ocular optic is common to both halves of the system. That means that either the main primary (the "whole picture" view system at the end pointing to the subject) or the periscope (the rangefinder) primary has become misaligned. Luckily, that means that you won't have to monkey with the mechanism at all. My first thought would be to look for any signs of damage to the unit near the primary lenses; if a slight ding in the box has caused one of the lenses to shift, you'll know which one to work on and how to go about fixing the alignment. If it's a matter of one of the mounts having slipped, that should be easy to spot as well. There is a chance, though, that it's the cement holding one of the primaries in place that's the cause (due to age or heat at some point), and that may not be so easy to spot. It may make sense to remove both, clean up any existing cement, and recement the lenses.

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Thank you so much. This sounds like a very likely cause for the problem. I will investigate further. The unit is not easy to disassemble, but I will attempt to open it and adjust the lenses. –  Daniel Smith Sep 7 '12 at 20:37
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