37mm Mamiya RB lens on a Plaubel 4x5

[Timhop]

Hi folks,
I was wondering if anyone could assist with what is probably a rather dumb question. I recently acquired a Plaubel 4x5 with 4 lenses. Three are Rodenstocks but one is a Mamiya RB lens that fits onto a specially made baseplate. The shutter will fire independently of the Mamiya body but i have to take the lens off each time to cock it, but when it fires it’s actually open, then closes as you fire it then fires your selected speed. Whats going on here? Won’t i get normal operation without the body? My question is: what will coverage on a lens like this be? Will i have to use a 6x7 rollfilm back?
Sincerely
Tim

[Havoc]

The shutter will fire independently of the Mamiya body but i have to take the lens off each time to cock it, but when it fires it’s actually open, then closes as you fire it then fires your selected speed. Whats going on here? Won’t i get normal operation without the body? My question is: what will coverage on a lens like this be? Will i have to use a 6x7 rollfilm back?
Sincerely
Tim

That _is_ the normal operation. This is a leaf shutter lens for a reflex camera. So when it is on the RB and armed, the lens is open so you can see through your viewfinder. When you fire it, it closes, the mirror lifts (shutting off the viewfinder) and then it exposes the film. And it is the camera that arms the lens when it is on the camera, the arming lever is at the back, that's why you need to take it off each time.

You should use "mirror up" working. In that case the lens should close and wait. So you get time to remove the darkslide before exposing https://rb67.helluin.org/using/

No idea about coverage but the lens was made for 6x7.

[Tin Can]

There was a custom external cocking lens board made to mount, cock and fire any RB lens
Not Mamiya

Many were sold

Mine is somewhere...but not FS

Perhaps put in WTB

[xkaes]

I use the exact same lens on my Toko 4x5, but I made my adaptor on a Wista board. The lens is easy to use with a cable release. You can find complete instructions with diagrams, photos, and examples at:

http://www.subclub.org/fujinon/gonefishin.pdf

The lens creates superb results -- AND you can put filters on the rear of the lens!!!

Show us some of your results.

I hope you have a good front lens cap!!!!

[xkaes]

Looks like a very nice job of removing the four lens shade flaps, but I'd get some flat, matte, black paint and touch them up. Not only looks better, but might avoid reflections.

Fortunately, Mamiya Sekor made the lens with the long flange focal length of the RB camera, so using it on most 4x5 cameras is not a problem -- despite its 37mm optical focal length it will not require a recessed board! -- and the image circle is just a little smaller than 4x5" film. I'd say, PERFECT.

The only problem with some cameras is getting the front rail/bed out of the picture. The front of the lens has to stick out far enough so that this part of the camera is not in the picture. On some cameras this is easier to accomplish than on others.

[Gord Robinson]

The only problem with some cameras is getting the front rail/bed out of the picture. The front of the lens has to stick out far enough so that this part of the camera is not in the picture. On some cameras this is easier to accomplish than on others.

If the Plaubel is from the Peco Profia series there are two or three short rails available to solve the issue of having the rail show up in your picture.

[Timhop]

Thank you so much for all the useful information, guys. Much appreciated.