Hi, @pmeheut My post count is too low and I don't have an "upload and sell" membership here, so I'm not allowed to send PMs yet. I can't reply privately to your PM about your new lens. Apologies for inflicting it on everybody, but here's my response:
The locking ring I removed was no.2 in your picture - the inner one, next to the coupling cam. This locks the cam in place. When it is removed you should just be able to lift out the cam. Underneath there should be some shims. I found 3 shims of different thicknesses. I took out the thinnest shim, but that was too much adjustment and moved the rangefinder from front focus to back focus. As I said my earlier post, I found the right intermediate adjustment by using a thin layer of clear nail varnish without replacing the shim I removed.
The cam only goes back in one position, because there's a cutout at the base of the cam that aligns with a screw in the body of the optical cell, so you shouldn't have a problem aligning the cam. Just make sure it's properly seated, otherwise the cam will be too close to the sensor for the focus distance of the lens.
The adjustment only affects the rangefinder calibration, not the focus of the lens itself at the infinity stop, so providing that the infinity stop is properly calibrated on your lens, it's a question of finding the right shim combination to align the rangefinder correctly on distant objects when the lens is at its furthest stop.
As long as the cam surface and helicoid angle are machined correctly (they should be!), then the focus distance should coincide with the rangefinder alignment at all distances.
Hi, @pmeheut My post count is too low and I don't have an "upload and sell" membership here, so I'm not allowed to send PMs yet. I can't reply privately to your PM about your new lens. Apologies for inflicting it on everybody, but here's my response:
The locking ring I removed was no.2 in your picture - the inner one, next to the coupling cam. This locks the cam in place. When it is removed you should just be able to lift out the cam. Underneath there should be some shims. I found 3 shims of different thicknesses. I took out the thinnest shim, but that was too much adjustment and moved the rangefinder from front focus to back focus. As I said my earlier post, I found the right intermediate adjustment by using a thin layer of clear nail varnish without replacing the shim I removed.
The cam only goes back in one position, because there's a cutout at the base of the cam that aligns with a screw in the body of the optical cell, so you shouldn't have a problem aligning the cam. Just make sure it's properly seated, otherwise the cam will be too close to the sensor for the focus distance of the lens.
The adjustment only affects the rangefinder calibration, not the focus of the lens itself at the infinity stop, so providing that the infinity stop properly calibrated on your lens, it's a question of finding the right shim combination to align the rangefinder correctly on distant objects when the lens is at its furthest stop.
Then, as long as the cam surface and helicoid angle are machined correctly (they should be!), then the focus distance should coincide with the rangefinder alignment at all distances.
Hope it works!
Feb 26, 2026 at 09:58 AM
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