Them's sure a lot of pixels.

Medium format camera, so it's designed at the more pro end of the market - lots more pro than I'l ever be anyhow.

In a shrewd marketing move the Mamiya ZD is also available as back which can be used on non-digital Mamiya SLR cameras - these cameras aren't cheap, so helping customers leverage their existing infrastructure is a really good move. Also, it helps with vendor lock-in, but let's assume that the Mamiya folks are just good hearted, shall we?

DigitalPhotographyBlog has more information.