with this lens at 45mm vs the Mamiya's one at 50mm, let me ask, why not the mamiya 50mm ? it is already proven to be a good lens.
Unless it is a 35mm shift for the Mamiya mount, I don't see any reason for moving to the 45mm... for the tilt maybe ?
I've built up a quite a kick ass linhof 69 system with digitar lenses for use with my leaf65 back, with bells like live view, but it is still
too much of an overkill for a commercial guy like me, I would like to get a 35mm to have for occasional use with the Mamiya.