To Juhani's question, here are the test shots I made last summer with a small sample of my FSU lenses. I like to use such lenses on the XE-2 because, due to the smaller size of the sensor, you are only using the central portion of the lens coverage, so the rendering is quite homogeneous. My benchmark is a line of 50's/60's Canon LTM39 lenses (from 19 to 135mm) which are astounding, and the FSU lenses of similar vintage are really on par with them (actually Canons are a tiny-tiny bit better, but hard to see, and their market price is 5- to 10-fold !) ; interestingly, and may-be contrary to the legend, the FSUs perform better than the Leica lenses of similar vintage in my inventory. I did not try 35 nor 90mm. First a Jupiter 3 :
Is there much difference in the edge performance of the different Canon Vs FSU VsLeica lenses. I presume there is, but most subjects aren't at the edge of the photo so it's not too important.