Don -


That's an interesting test --- thanks for organizing and sharing that. You made a comment that tilting the lens affects exposure --- this is true (as it is for shifting), and can be easily corrected by simply shooting in live view mode. Also you are correct that the DOF is wedge-shaped when you tilt. See this article for an illustration of this effect:


http://www.cambridgeincolour.com/tutorials/tilt-shift-lenses2.htm


Jonathan