The Cambo X2-PRO Lensplate, XA-232 makes it possible to use Mamiya 645 Pro lenses in combination with the X2-PRO system.
Mamiya 645 Pro lenses can be set manually to the desired aperture setting in the contrary of Mamiya 645 AFD lenses.
The XA-232 can only be used in combination with Canon bayonet based SLR bodies and will not work with Nikon bayonet based SLR bodies.
The use of a Mamiya lens relates to your sensor size as the same focal length in 35mm format. For example a 45mm Mamiya lens will have the same perspective on a 1Ds as a 45mm Canon lens.