I bought this a couple of years ago on Ebay, and am now getting ready to mount it on the 8X10 Seneca. It's way too heavy and the flange is too big to mount on a lens board and hang on the front standard, so I will need to build some kind of a cradle to rest on the bed and slide the lens back into the front standard. If I install the extension rail and rack the rear standard back onto it, I should be able to focus the beast somewhat closer than infinity.
The lens is lacquered brass and completely unmarked except for the shell of a Wollensak Studio shutter No. 3, Style B. Some previous owner removed all the shutter's innards, so now it's wide open and shutterless. Checking the old Wollensak catalogs, the lens looks externally very much like a Series A (Vesta) No. 5., except the hood is longer.
But internally, I think it's different. I gather the Series A and later Vesta were Petzval types, but after taking the cells apart to clean all the surfaces, which it needed, the design seems to be different from a Petzval. I did some careful checking of reflections and curvatures, and this lens appears to be like an extra rapid rectilinear with an extra thin weakly positive meniscus element mounted next to the rear cemented doublet on the diaphragm side. This meniscus element is spun into it's own thin cell that screws into the back of the rear doublet cell, so it wasn't added as an afterthought. There is a faint hint of overall haze in the cement layers of both doublets that can be seen by shining a strong light on the doublets at a shallow angle and by looking through the doublets at a strong light source. It shouldn't be bad enough to seriously impair performance, but it does allow me to see the deeply curved cement interface in each doublet.
I drew a rough freehand sketch diagram, not to scale, but it should show the optical layout. I haven't found this in Kingslake or any other reference I can find.
Any ideas who might have made this lens or what type it might be?
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