Compared: Leica 35mm f/1.4 Summilux-M ASPH FLE vs Zeiss 35mm f/2 Biogon
Published in my Guide to Leica is a definitive study of focus accuracy, focus shift and sharpness (and field curvature) at a distance of ~1.2 meters using the Leica 35mm f/1.4 Summilux-M ASPH FLE and a Zeiss ZM 35mm f/2 Biogon adjusted by the factory to “optimize for digital rangefinder camera”.
I expect this study will prove useful to those choosing a 35mm focal length for the Leica M cameras, and it should also prove quite instructive to those wishing to get the very best results from either lens.
Order either lens through my Leica gear pages.