The Schneider lenses that have built in Canon EOS mounts do not have electronic aperture control, and so you must set the shooting aperture for every shot using the mechanical preset ring on the lens. It has been over 40 years since I had to stop down before shooting, so I am sure I would never adapt well to that shooting workflow. The whole concept of a DSLR is you can see and focus at full aperture and then shoot. I guess with live view you may be able to frame some shots OK while stopped down, but judging and getting critical foucs really requires a wide open lens.
I know the Schneider prices were also quite high, but do not remember specifics. It would be great if someone would post the approximate prices for the Canon and the Schneider version of the 90mm tilt shift lenses.
The 90 TSE enjoys an enviable reputation as one of Canon's sharpest lenses with great color reproduction. It shoots close-up into the macro range, as well as the electronic aperture mentioned by Roland. The design is unchanged from the mid-90s -- that says something positive.
