[Leica] R and M lenses

["Erwin Puts" <imxputs@knoware.nl>]

I cannot possibly comment on all M and R lenses that are close focusing and
wide angle. That would be a booklength document.
Generally however, retrofocus designs, when designed competently have more
potential for aberration correction than the symmertrical equivalents in
focal length. The R lenses focus more closely than their M partners. The M
mechanical linkage and Paralax cannot handle it. Generally when focusing
close, image qulaity drops as lenses are not optimised for close focus.
Since the technique of the floating elements, this problem is overcome and
current Leica enses from 19 to 35 have these elements.


Erwin