This one thing I will say is that they are my personal favourite type of camera as I feel that they most represent what I see. I also like the immediacy of the action with a rangefinder or SLR, there is very little in the way of setting them up. In 35mm it doesn’t make all that much difference, but when you are using medium format becomes more of a challenge to be able to take pictures on the fly unless you are extremely familiar with your camera, but with rangefinders you are going to be able to shoot in a more informal fashion. The Mamiya 6 system, introduced in May 1989, is a 6×6 cm (2¼" square) rangefinder camera taking 120 and 220 film with three interchangeable lenses of 50mm, 75mm and 150mm. The Mamiya 6 does the same thing as a Hasselblad system with 50, 80 and 150 lenses, just that this Mamiya weighs much less, is much easier and faster to use and makes sharper images due to the silent and vibration free electronic leaf shutters and rangefinder-design lenses. 220 and 120 film is selected just by rotating the pressure plate; the Hasselblad requires separate backs!
This rangefinder design is what makes the lenses better than the Zeiss SLR lenses exactly in the same way the Leica rangefinder lenses can outdo SLR lenses, especially for wide angles. The Mamiya 6 system, introduced in May 1989, is a 6×6 cm (2¼" square) rangefinder camera taking 120 and 220 film with three interchangeable lenses of 50mm, 75mm and 150mm. The New Mamiya 6, discussed here, came out in 1989. Except for the film format and name, it has nothing in common with the original Mamiya 6. It is called New Mamiya 6 among camera historians to differentiate it from the mechanical camera above, otherwise, everyone including myself simply call this the Mamiya 6. This is my favourite version, and actually, my favourite camera of all time.
One of the biggest names when it comes to medium format rangefinder cameras is Fujifilm, and over the years they have produced a simply massive amount of cameras. In the early days Fuji cameras were made as Fujica, which was a contraction of Fujifilm and Camera, later just be called Fuji or Fujifilm cameras. I am not really going to sit here and list all of the cameras that they produced over this time, Camerapedia is better for that. But I am going to give you some notable cameras that are very much worth looking at.
The Fujica G690 was the first of the rangefinder cameras that Fuji produced, and all of the ones that came after can trace the lineage to this camera. It was developed to fill a gap in the market, where professionals needed the speed of a 35mm in larger format. The Fuji filled the gap perfectly and sealed the reputation for Fujifilm. The notable thing about this camera is that it was one of the few Fuji rangefinders that had an interchangeable lens system, later cameras came with fixed lenses. These cameras have become harder to find in the last few years as they are getting on in age and the professionals were not all that kind to them, you can expect to pay around 707.48 United States Dollar for a clean Fujica G690 with lens. For a late model Fuji GW690III with low shutter actuations you can pay around the same. These cameras can be a bit sensitive and it is worth trying to find one that has not been shot all that much.