165mm f9.5 Wollensak Velostigmat Series III 8x10 WA

[Ed Bray]

I was doing a bit of research trying to discover the approximate age of my newly arrived 165mm f9.5 Wolly. I was surprised to find in the Wollensak Lenses and Shutters Catalog 1916 on Camera Eccentric a) that it covers 8x10 at f9.5 and 10x12 stopped down (I had understood it just covered 8x10) and b) and even more surprising, that the lens was designed as a convertible using either the front or rear lens only and giving approximately twice the focal length (extract from Brochure quoted below):

“Particular attention is directed to the fact that the Series III is a convertible lens, each element being corrected for use alone and each being about twice the focal length of the doublet.”

So, how do I find out the approximate aperture to use when I try one of the lone groups? and has anyone here ever tried it and if so was it successful or not?

TIA

[JimL]

For double the focal length, if you remove the rear cell the aperture number should approximately double or be 2 stops higher - so set at f11 to get f22, f16 to get f32, etc.