Quote Originally Posted by EdSawyer View Post
The RZ67 was designed to replace the RB from the get go. No doubt whatsoever. It was only later that they finally realized people were going to keep buying the RB (for whatever reasons) and decided to keep making them. I am sure they would have preferred to not bother, probably. But the money was too good, I'd guess.

What functionality was lost? None that I can think of. Everything was/is a gain - which is why it was designed as a replacement. the RZ is a superb system, and especially these days with the crazy cheap prices, no reason not to choose it over the RB. RZ lenses are actually cheaper in many cases than RB lenses (more of them available, the APOs for example).

-Ed
I think another the reason for the co-production of RB/RZ systems was because many people were skeptical of the electronics and potential for battery failure (whether it be on a long, demanding shoot or outside in battery-defeating temperatures). Yes, there are work-arounds that we're all familiar with now, but that's like Monday afternoon quarter-backing (after the Sunday game) - hindsight almost always gives perfect clarity.

For my purposes, I (generally speaking) have chosen not to buy cameras which require a battery and chose the RB67 Pro-S for that reason. In hindsight, I wish I had chosen the Pro-SD, but I'm very pleased with my Pro-S all the same (even the 120 backs which need to have the light-seals maintained). My 35mm gear all requires a battery for some level of functionality (whether just for the meter or for both meter and shutter), but I tend to prefer the least amount of electronics for my film gear.