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doubice · 03/03/12, 19:10

I believe the issue is that the lens mount is not perfectly flat. This could be for two reasons - either some washers missing under the lens mount or, a warped body. By tightening the lens, uneven force is applied to its helicoid and thus the focusing action becomes 'sticky'. The only way to check this exactly, would be using a depth measuring micrometer (body lens mount vis-a-vis pressure plate) or a collimator.

I have had a similar issue with a 1.5/50mm Summarit and it only happened on one body, when the lens was tight in the mount. I paid no attention to it, as I had a few other bodies where the problem was not present.....

Best,

Jan

03/03/12, 19:10	#9 (permalink)
doubice Erfahrener Benutzer Join Date: 09/01/04 Location: Vancouver Posts: 2,000	Re: Leica Screw Mount Lens Issue I believe the issue is that the lens mount is not perfectly flat. This could be for two reasons - either some washers missing under the lens mount or, a warped body. By tightening the lens, uneven force is applied to its helicoid and thus the focusing action becomes 'sticky'. The only way to check this exactly, would be using a depth measuring micrometer (body lens mount vis-a-vis pressure plate) or a collimator. I have had a similar issue with a 1.5/50mm Summarit and it only happened on one body, when the lens was tight in the mount. I paid no attention to it, as I had a few other bodies where the problem was not present..... Best, Jan