That's exactly why I got into a CL. Wanted a little bitty camera that could take modern Leitz glass. Make it from an Altoids tin, I don't care; just let me use these lenses.
Knee-jerk review: So far, if my two test rolls are anything to go by, I find the 50mm Summicron-M to be a lot gentler than my comparatively relentless 40mm Summicron-C.
I like the crunchy brutal aesthetic of the 40's pictures more, but this 50 is extremely well-mannered, and has an angle of view more like my brain's. The 40's out-of-focus areas are superb, but the 50's bokeh is just... whoosh.
Guess I'll have to keep both.
"Ooooh...I like that. A lot."
Thank you, ma'am.