Differences in the old, pre-C Mamiya RB lenses

[Mamiya_Repair]

It's interesting how that table specifies "RB C" lenses. I can't think of any reason why, non-"C", "RB" lenses should not be included. As far as I know the only difference with the "C" lenses is that they are multi-coated.

There is a good reason that the non-C lenses should not be used with extension tubes: The earlier lenses (non-C) used a different shutter (a Seiko 653) that required more energy to cock the mechanism. When used with an extension tube, the camera is under even more pressure to cock the shutter and this can lead to camera failure. Same reason that these early lenses are not torque compatible with the RZ67 when using RB lenses on the RZ and can lead to early failure of the already strained RZ67 cocking mechanism.

{Moderator's note: thread created from posts that originated here: https://www.photrio.com/forum/threads/mamiya-rb67-pro-s-extension-tube.206741/}

 

[xkaes]

And all this time I thought the only difference was the coating -- much like the Minolta Rokkor vs Rokkor-X lenses. Thanks for the education.

 

[Mamiya_Repair]

And all this time I thought the only difference was the coating -- much like the Minolta Rokkor vs Rokkor-X lenses. Thanks for the education.

While the coating was one of the differences, the new shutter style on the C lenses provided for an external sync socket that could be replaced when worn. The earlier lenses had the sync socket as part of the shutter housing and it could not be replaced without replacing the entire shutter. And, the 65mm C and 90mm C lenses had new formulations that took advantage of the new 30mm shutter opening.

 

[MattKing]

Thanks Mamiya_Repair.

 

[xkaes]

Is there a table somewhere with all of the RB lenses by series -- such as focal length & f-stop on the left (Y-axis) and series/features on the top (X-axis)?

I've never taken the time to SEARCH. I only have the 37mm f4.5, and I know there were several versions of that one alone!

 

[ags2mikon]

I can add that the 250mm non "C" is a different design than the "C" version. Some were the same like the 127mm.

 

[Alan Edward Klein]

Here's a cross-reference chart for RB67 and RZ67 cameras, lenses and auxiliary equipment.

 

[ags2mikon]

Thank you Alan. I just saved that.

 

[xkaes]

Here's a table of some of the C lenses. It would be nice if there were a list including the earlier pre-C lenses, and the later lenses too -- barring that, just lists from the Mamiya product literature.

 

[MCB18]

Can the newer, NB lenses be used with extension tubes? I planned to use my 90mm NB with no.1 and 2 tubes so that I could take 2:1 macro shots.

 

[Mamiya_Repair]

The NB style lenses (65mm, 90mm 127mm) were produced briefly in 1974 and used the old style high torque 653 shutter. So while you can use them with extension tubes, just keep in mind that extra torque is needed from the body winding mechanism to cock these shutters when using tubes.

 

[xkaes]

Is an alternative -- even though a nuisance -- to manually cock the shutter before attaching these lenses to the camera? I do that all the time with my 37mm C lens.

 

[Mamiya_Repair]

Is an alternative -- even though a nuisance -- to manually cock the shutter before attaching these lenses to the camera? I do that all the time with my 37mm C lens.

I don't see how that would work since you have to cock the lens before taking it off the body.

 

[xkaes]

Right, but I always release the shutter in the lens after I remove the lens from the camera -- as the manual recommends, if the lens won't be used for a while.