My friend Brian Kleiber just got an camera recently an Mamiya RZ67 professional and went to the street to capture some moments. He mention that the camera had some light leaking at the beginning and he lost couple of shoots but now he fixed and is waiting for new results.
In those frames he used the Mamiya R7 67 + Fuji Pro 400H with 65mm f4 lens, that is a super combo that can generate amazing results.
The Mamiya RZ67 is a professional medium format single-lens reflex system camera manufactured by Mamiya. There are three successive models: the RZ67 Professional, RZ67 Professional II and RZ67 Professional IID.
All the credits to: Brian Kleiber