I have both Leicas and an Xpan, the Xpan produces very sharp negs, comparable to Leica at 36x24 and everso slightly softer at the ends of panoramic for the 45mm and as sharp at the ends (no point doing corners here) with the 90mm. Slightly OT, I have been using the CV 35mm f2.5 M mount a lot recently, better than my 50 'cron (rigid 1st type) for sharpness.