I bought a Carl Zeiss Jena Triotar 135 f/4 with stiff focus-ring. I disassembled the lens to fix the focus ring, work done.
But now I would like to disassemble the lenses as well, because the internal lens is dirty and I want to clean it.
In front of the objective I can't see any screws or notch to unscrew the lenses. In rear there are three notches, for three different screwed-rings.
Which one must I unscrew to disassemble the lens?
General advice about old Zeiss lenses like that:
Photograph the exact position of all rings and their notches (also, mark the rings beforehand to avoid 180° confusion) with a cellphone or similar, so you can reproduce the exact positions later.
Zeiss often used adjusting rings that affect centering...
Also, the materials used back then tend to be brittle, and threads stuck very, very firmly. Forcing such threads open after 70 years can shed metal particles ... make sure you clean them up.
