Mount a random lens in shutter on RB67 -- anyone done it?

[Donald Qualls]

Seems fairly basic and obvious how -- make a lens board attached to an extension tube, of length suitable for the focal length, and treat it like large format lens. Lock it open on B or T for focus and composition, stop down and close shutter, cock shutter, fire the body, fire the shutter, then cock the body and advance the film before opening the shutter for the next cycle.

Question is, what would be the advantages? Design the lens board for it, and you can have shifts; and you can use focal lengths and lens types Mamiya never offered -- 105mm, 120mm, 135mm, 150mm (likely anything longer than about 90mm would work with a short enough extension tube or mounted on a body cap). Maybe just an exercise in adding versatility to a body that can already shoot three frame formats (four if you count 35mm sprocket panoramic) with something like eight different lenses, plus teleconverters and macro rings.

Do I need to mount a 105 mm when I already have a 90mm and can easily get a 127mm? No. Do I need a Tessar type or triplet or Rapid Rectlinear or whatever when I've already got whatever (assymmetrical double Gauss?) the 90mm lens is? No. Then again, do I need cameras in current and obsolete formats from 16mm to 4x5, including multiples in most of those? Of course not.

Has anyone tried this, or something similar? It's kind of in the same class as the new 3D printed medium format designs, only MUCH heavier, and an SLR.

 

[Maris]

I purchased a bargain Mamiya 65mm lens from Adorama with bad glass but a good shutter. After taking all the original glass out I have a working "lens" into which I can insert experimental glass elements or alternatively attach real lenses to the front. The advantage is the set-up focusses and fires like a RB lens. The downside is the small shutter opening will cause vignetting if I use a too long focal length.

 

[Digger Odell]

Well, not exactly. I did this the other way around, and 3d printed and adapter to use the RB lenses on my 4x5 rig. No they don't cover 4x5, but I can use the movements, then crop (in the darkroom) to 2x3 or whatever. The hard part was adapting a way to cock the shutter with out removing the lens each time. I sacrificed a "as is" body from KEH for the mount/cock portion. Now IF I had a 4x5 to 2x3 roll-film back, I would be all set to take medium format pictures, with movements, and "RB lens quality" One problem is that my 4x5 is a cambo rail camera. (not very portable) I kind of backed off this project when I "discovered" the baby graflex. This has kind of got me thinking about adapting this lens adapter to the graflex front standard. As my goal has been medium format with movements, and portability.

Update: the front standard on the baby graflex is too small for this to bolt right on. It might fit with some major modification to the adapter.

The little brass lever is to cock the shutter and works fine.

 

[Donald Qualls]

Nice! Too bad the "normal" isn't a little longer; I've got a 105mm triplet that just covers 4x5 (at f/16, if you focus to 12 feet or closer). That, and a 150mm Tessar I have for my Ideal plate cameras, were the lenses I was thinking of when I wrote the original post.

 

[ic-racer]

Unless one really wants to stay with the RB body, the situation spills over into the medium format technical camera realm. Once you move to a medium format technical camera body, the options lenses, backs and modifications are ten-fold greater.

 

[Donald Qualls]

Unless one really wants to stay with the RB body, the situation spills over into the medium format technical camera realm. Once you move to a medium format technical camera body, the options lenses, backs and modifications are ten-fold greater.

Then again, a basic MF technical camera, with one lens and one roll film holder, will cost roughly as much as I've got into my RB67 with four roll film holders (6x7, 6x6, 6x4.5, and a 220 6x7 that I use for 35mm pano), three lenses (50, 90, and 250) plus a 2x teleconverter, and now metered chimney and unmetered prism finders in addition to the WLF.