I have one of these and it is easy to take on and off and works well. It acts as an extension, though and I use it with my Macro lens for real closeups. If you wish to use it for normal distances, you must have the short-barrel lenses which are made for it. I have RZIIs but I think it should work on an RZ. There are quite a few on eBay normally, but the short lenses don't come up as often. The prices now are really right..Evan Clarke
Anytime you move the lens away from the designed plane of focus your going to decrease the actual distance that the lens focuses at, so I would imagine that by putting the shift adapter in the mix even your 50mm is going to focus closer and have difficulty with infinity focus.