Sure there are... I'm using my CF-39MS on Contax 645 currently... The CF backs have user interchangeable adapters for almost all MF cameras that ever existed and they have the additional benefit that the adapter is the same no matter the model of the back or if it is Imacon or Hasselblad... All adapters fit all imacon or Hasselblad backs. My CF-39MS for instance, was H-mount when I bought it and I used the adapter plate of my Imacon 528c back on it and then sold the 528c as Hasselblad H-mount...