IMO, there is no way the 40 FLE matches the S35 out to the edges. The Zeiss 40IF may come closer or match the S35, but that improved edge-to-edge performance came at the price of increased distortion over the 40FLE. The Hasselblad HC 35-90 is almost as good as the 40IF @ the 40mm mark, and it’s a zoom.
So far the S35 is the best MFD wide angle I’ve used. I skipped waiting for a 30mm because I want something wider like the promised 24mm … 30 to 70mm is to wide a gap in the focal length jump for me, and 30mm is a bit to wide to shoot groups of people. Not interested in a 35-90 zoom …. it’ll be too big and for sure it won’t be fast. I have the HC 35-90 for my H4D/60, and it is a monster.
(I’ve owned and used all the above, plus the Contax 35 for the 645 (which also exhibited distortion).
But, it is really convenient to now be able to use other lenses for specialized work. The Zeiss 120 macro isn’t optically as good as the S120 or the Contax 120, or the HC/120 … but compared to the S120/2.5, it stops down more to gain DOF … and you can use tubes to get a 1:1 ratio.
-Marc