See my L-mount mirrorless wishlist
The Leica 50mm f/1.4 Summilux-SL ASPH sets an EXIF flag that requires software correction for both color fringing and distortion. For a lens claimed by Leica to be a “reference lens”, requiring distortion correction seems dubious at best because a requirement for distortion correction guarantees reduced performance in some part of the frame, since pixels have to be stretched apart to correct the distortion. And yet the distortion is strong enough that it really has to be corrected.
The degrading effects of distortion correction in both single shot mode and especially Multi-Shot High-Res mode are well worth understanding for anyone thinking of high resolution capture. In diglloyd L-Mount Mirrorless:
I also discuss MTF in depth, noting two points that make the Leica MTF charts misleading at best:
Based on working with both the Leica 50mm f/1.4 Summilux-SL ASPH and the Leica 16-35mm f/3.5-4.5 Super-Vario-Elmar-SL ASPH, I would say that any assumption that Leica SL lenses are a magic bullet for resolving power on the Panasonic S1R is a poor assumption at best. Stay tuned for lens comparisons!