Tonight's Fun: Taking Apart 1890s Barrel Lens
I was curious about the rear lens elements of the old William, Brown, & Earle Philadelphia lens I have so I took it apart. Suspecting this was a Petzval design, I expected two air-spaced elements of a certain shape (there is), but there is also on the innermost surface a third very thin (and chipped) convex lens. It seems auxillary, but I wonder what it exactly does. Likely some small correction or perhaps a power booster. In any case I might try to shoot without the rear elements just to see what'll happen....
