You can purchase a number of quality digital backs for the major medium format systems like Hasselblad or Mamiya to replace your film back. These backs are all designed for the traditional medium format shooters - highend professionals - and as such are expensive. Very expensive. Even the used ones are expensive - like $1k for a 6mp Phaseone. They are also among the highest resolution digital cameras available - a PhaseOne P45 is a 39 MegaPixel back that produces a 117mb file. Seriously high quality images and cameras that are pretty much reserved for highend commercial photographers, since for all but those with $10k day rates a good Canon or Nikon produces almost indistinguishable images.