[mst]

Ask Markus about the vignetting ...

Yep. Peak value measured is above 5 EV, IIRC. And no, that wasn't a cheap 3rd-party lens...

Vignetting numbers are generally much higher on the M9 than what we're used to with a DSLR (any sensor size).

And 90mm are about the finish line in these system. A 300mm lens will be barely any smaller than on a DSLR.

The Leica 135/2.8 is already quite large. On a small camera (that's what we're all hoping for when dreaming of a full-frame mirrorless, right?) too large and too heavy. The combo is already quite arkward to handle.

-- Markus