[Leica] 50mm Summicron-M vs Summilux-M

["The Adler Family" <badler@nanospace.com>]

I apologize if this question has been asked before, but I have not been able
to find a succinct answer to this question even after a thorough search of
the digest's history of Erwin's reviews. I am a recent purchaser of an M6TTL
(0,85), 35mm ASPH Summicron-M and 90mm Elmarit-M. I am considering the
purchase of either the 50mm Summicron or Summilux, and was wondering about
the difference in their performance.

My main reason for the purchase of the Summilux would be to have the low
light capability when needed (if ever). I like to have as many options as
possible.

However, from f2 on up, do these lenses behave differently? Is there a range
wherein the Summicron out performs the Summilux  (say from f2 - f 2,8 or
from f2 - f??) and then any differences become negligible?

I would appreciate any answers, both from a practical use perspective and
from a purely test environment perspective.

If I have missed this thread or if Erwin (or anyone else) has done such a
comparison, I again apologize for taking up bandwidth and would appreciate a
pointer to that location.

Thank you in advance for your opinions.