What's the difference between Mamiya RZ and RB lenses?

[Mainecoonmaniac]

I own an RZ system for over 20 years. A while back, I bought an RB lens to use with my RZ body. I have to admit that I screwed up a roll of film and I adjusted the shutter speed on dial on the body with my new RB lens. Oops! Other than the mechanical shutter in RB lenses are there differences between the lens systems? Are there differences is lens quality?:confused:

 

[TimmyMac]

Depends on the RB lens you're talking about.

The newest RB K/L lenses are identical to the RZ lenses, except for the mechanical shutter in place of the electronic RZ ones.

The older ones are older designs with older coatings, whatever difference those may make.

 

[polyglot]

As TimmyMac says, the newest K/L lenses are equivalent to the first RZ lenses, but most of the RZ lenses have been refreshed since then. 110/2.8 and the 50/4.5 ULD are not available for RB because (I think) they have a too-large exit pupil. The film/flange distance is shorter for RZ than RB (less retrofocus required for wideangles), and the RZ camera throat is larger (larger exit pupils possible, e.g. for the ULD, 75-shift and 110).