Mamiya 6 is a 6x6 medium format rangefinder camera system with three interchangeable lenses of 50mm, 75mm, and 150mm. It was introduced in 1989 and discontinued in 1995. There are two main models: The 6, which has a few variants, and the 6MF.
These cameras were designed for professional use and built around a collapsible lens mount. This makes the Mamiya 6 one of the smallest and lightest medium format cameras out there. The 6MF version can use a 35mm panoramic kit, allowing 56mm wide frames (about double normal width), qhich is similar to the aspect ratio of the Hasselblad XPan. These also have marks on the frame lines in the viewfinder indicating the 35mm panoramic format as well as 6x4.5 framelines.
The three focal lengths are all shown in the viewfinder/rangefinder. Note that these lenses are not compatible with the Mamiya 7 and the Mamiya 7 lenses are not compatible with the Mamiya 6.
These camears are operated in much the same way as 35mm rangefinders, with lens-based focusing and aperture control and a shutter dial on top. The camera is capable of aperture-priority auto exposure with it's center-weighted average light meter. Unfortunately, metering in manual mode only works in full stops, making precise metering (for slide film in particular) a bit difficult.