This lens mount adapter allows a Hasselblad Bayonet lens to fit on a medium format film/digital Contax 645 camera. Although the lens will fit physically, automatic diaphragm, auto-focusing, or any other functions will not operate correctly while using this adapter. In this case stop-down mode will need to be used when metering since the lens does not have the ability to have its aperture controlled by the camera body. You can shoot with manual mode or aperture priority mode with the Contax 645 camera body. Infinity focusing is guaranteed.