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
My first thought, too. Its almost identical to the image from wikipedia’s article on petzval lenses, even.