Robot Royal fit Carl Zeiss Sonnar 50mm f2

[archive59]

I have just received a Robot Royal 36 fit Carl Zeiss 50mm f2 lens (Nr.1744422). The focus ring was loose and while investigating this and how it all fitted together I have managed to unscrew the optical unit from the body. I can screw it back in but only as far as the two small posts that need somehow to be lined up with corresponding slots in the optical unit and then continue to screw in. Even if I managed this I am not sure my infinity focus is going to be correct now. Can anybody give me any pointers as to how I might get the lens sorted. I suspect this will require an understanding of the Robot Royal lens construction rather than CZ optics but then again if I knew anything I would not have got myself in this mess!

Mark

 

[Sonnar Brian]

I've not handled or worked on a Robot Royal- but, the standard Zeiss optics module is held in place by a retaining ring coming in from the rear. It also has a guide post. SO: the optics have to be pushed in, lined up with the rail. Then, you tighten it in by screwing in the retaining ring at the back of the lens.

Post some pictures of the module and focus mount. Usually, Zeiss used a standard optics module and the mounts were made to accommodate it.

 

[Edward C. Zimmermann]

I have just received a Robot Royal 36 fit Carl Zeiss 50mm f2 lens (Nr.1744422). The focus ring was loose and while investigating this and how it all fitted together I have managed to unscrew the optical unit from the body.

On the Zeiss Sonnar the focusing rings--- the thing with the 3 tabs--- is just bolted onto the focusing sleeve and the sleeve bolted with again, I think, 3 set screws onto the unit. The sleeve construction is a bit different from the typical Robot objectives--- those from Schneider--- as its handled internally and there are not the two pins blocking the movement in the right and left direction. That's why by removing the screws on the sleeve the whole unit fell out.

I can screw it back in but only as far as the two small posts that need somehow to be lined up with corresponding slots in the optical unit and then continue to screw in.

Yes.

Even if I managed this I am not sure my infinity focus is going to be correct now. Can anybody give me any pointers as to how I might get the lens sorted.

The typical means--- which is "good enough"--- is to put a ground glass on the film plane--- there is even a Robot accessory with a clip-in and fold over ground glass to make this even easier but they are quite rare--- and adjust until the focus is right. Measure the distance to object and focus. The rest should fall into place. The rangefinder focusing cam is the sleeve under the ring--- on the Schneider objectives its one piece (sleeve is ring).
Once it right you tighten it down and then can install the ring and tighten it down--- in fact you don't need to have the ring at all it just provides a surface for focusing and the 3 tabs.