My newly acquired Rochester Optical 5X7 Reversable Back Premo came with a Zeiss Convertable Anastigmat mounted in a wonderfully complex Bauch & Lomb shutter. Unfortunatlely both cells have significant annular separations that mar an otherwise magnificent lens. While I expect that the best thing to do is to leave them alone, I have read that in some cases the cemented pair can be separated and re-glued. Has anyone attempted this, and how successful was the effort?

Also, the cells are marked 11 1/2" and 14"; can anyone tell me what the FL of the combinaiton is?

I'd say somewhere around 7 1/4 inches. The scale on the shutter should have three scales, each marked at one end with the focal length.

Although SK Grimes no longes recements lens there is some good information available there. http://www.skgrimes.com/popsci/index.htm

I don't know if he still does recementing of lens elements but Konny Lang of Atlantic Camera Repair, 10 Roderick Road, West Islip, NY 11795-2816 recemented the lens on a Zeiss Contaflex for me about twenty years ago.
It might be worth the cost of a postage stamp to inquire of him if you can't do it yourself or find someone that will do it for you.

C. Henry

It took a bit of looking but I found the third scale; the FL appears to be marked 7.5", close to Les' estimate.

I think for now I'll leave the glass alone. Maybe later I can experiment on something more disposable before trying to separate and recement the Zeiss. I did note that the front cell appears to have three cemented elements, which rather surprised me as I was expecting a pair.

According to the Vade Mecum, the Zeiss Series V11a are a double Protar with a 80 degree angle of view.( the cells when sold seperately were listed as series V11) Each cell is fully corrected with little or no flare. The cells are a 2 + 2 Anastigmat 4 glass design. It is not clear which design fits the V11/V11a but there are 4 2 + 2 designs that are very simular. The differences are the thickness of an element or the reverse order of the elements, angle of the inner element edge clip.
Basically (1)Thick outer element convex outer surface, concave inner surface with tapered edge;(2) matching convex outer surface angled edge to match first element in some diagrams, forms a step in others, shallow concave rear surface; air space(+);(1) concave front surface, tapered edge matching previous pairs, concave rear surface;(2)convex front and rear that matches the previous element. Description in direction of light travel.
Once disassembled you may find that only one pair needs to be recemented in each element, should be an easy fix.
Charles