M10 Monochrom viewfinder focus issues

[leica-curious]

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Any suggestions to explain why photographs taken using viewfinder focus on an M10 Monochrom with the 35mm Summicron f2 (v4) or 35mm Summilux f/1.4 (reissue) seem to not be in focus, but those taken with the 35mm Summicron f2 ASPH (v2) are in focus?

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[spydrxx]

Perhaps your lenses and body are out of calibration. Have you tried those lenses on another body?

[leica-curious]

I believe the 35mm Summicron f2 (v4), 35mm Summilux f/1.4 (reissue) and 35mm Summicron f2 ASPH (v2) have no issue on film cameras.

Edited June 24, 2024 by leica-curious

[dpitt]

If they seem to work well on film camera's that indicates they are not far out of calibration. It is hard to compare but depending on the film used, resolution of film is between 8 and 20 MP.  this means that maybe you never noticed the differences on film because of the lower resolution.

Did you do a test on tripod with careful manual focus, and compare that with the optimum focus using LV and magnification focus aid?
Compare all three lenses this way and at different apertures. 

The Summilux 35 pre-ASPH was known for its focus shift issues. So even if you focus correctly in the RF, it will be slightly off in a certain direction depending on the chosen aperture. This cannot be fixed by calibration, it is inherent to the design of this lens. The Summicron's are not known to have this issue.
I am not sure if the re-issue of the 35 Summilux has the same issues, but it seems probable.

[leica-curious]

I'm planning to run some tests on a tripod to rule out movement and keep distances fixed.