It has 4 lenses in total, two at each end. The only text on it is the number 50, stamped into the bottom of the ring that goes around the outside to attach it to whatever it goes with
It has 4 lenses in total, two at each end. The only text on it is the number 50, stamped into the bottom of the ring that goes around the outside to attach it to whatever it goes with
Camera or projector lens, probably of petzval type.
Edit: the lack of an iris or slot for waterhouse stops makes me think projector lens.
My first thought, too. Its almost identical to the image from wikipedia’s article on petzval lenses, even.
If you look at the photo of a magic lantern here https://blog.scienceandmediamuseum.org.uk/christmas-magic-lantern-slides/
The front lens cap is very similar.