I opened my 15" B&L Petzval Projection lens and that one has the ring between the two rear elements.

I'll do same when I come across my 18" and 10.5" B&L projection lenses but pretty sure they have the ring between them as I disassemble all lenses at acquisition and make sure the lenses are cleaned and assembled properly.


Quote Originally Posted by C_M View Post
If I put the ring between the elements and close the cell I will damage the elements, for sure.

As it came mounted (ring-lens-lens) the elements only touch each other very on the edge (+/- 1mm) and there is space between them on the rest of the surface. I tried it on the window with the cardboard and it seems that focuses mounted in this way ...
I need a flange to be able to test it with the camera.

Do you know any "petzval" that is mounted without spacer ring ??? ... (Element on top of element)