Interesting Schneider states the 50 "is therefore recommended mainly for architectural photography as well as for town and landscape imagery."
I ordered one when it was announced, but when they sent me the MTF's from Germany I couldn't quite believe the distortion graphs (over 2%). When I asked why they would design a modern lens with this much distortion they replied it was not intended for architecture but for table-top, and they recommended using a plate camera such as the Alpa for architecture.
That along with it not being a new optical design (basically the old mf SA in a new house), the cost of over $4k, and the shipping date being pushed back over and over led me to cancel my order.
I checked with my dealer, they have received a 90 but still no 50.
I have a 50mm on order and raised these points with Robert White - the UK distributor - this is their response:
The truth is that a Distagon design is required in order to make space for a mirror box as well as for the complex movements that are required for a PC lens
this type of lens design is also used by Zeiss for the Hasselblad system and is known from Schneider as the premium medium format Rollei lens 50/2.8. both these lenses have very high optical performance and have an image circle that it big enough to cover medium format, as well as being large enough to allow perspective control on full
If you look at the Canon and Nikon PC lenses they also use a Distagon design for the 24 and 45mm lenses... they do this because there is no other way .
We have also to remember that all lenses distort and for this reason Nikon Canon Zeiss and indeed Schnieder list MTF charts to document the lens performance. the selling point is that the Zeiss and Schneider 50 MF lenses have an even greater image circle that the Nikon and canon equivalent, this means a large sweet spot to the lens.
In terms of price the Schneider 50/2.8 lens in a Rollei mount used to cost around £2800 + VAT new. The Zeiss 50/4 CFE lens sells for £2700 new. so given that this optical design has been mounted into such and expensive tilt shift mount and costing a little over £2000 shows great value for money.
Having said all this if you look at the 90/4.5 PC TS HM lens you will notice that it has the image circle optical layout and performance of the 90/4.5 Apo macro Digitar lens.
Due to the focal length this lens does NOT need to be a Distagon ( retrofocus ) design and so is one of the finest lenses in the World .
I have not cancelled my order as I think that the points made are valid.