Hello, I recently got myself a Yashica-Mat LM. Directly after this I found myself wanting the Close-up lenses to go with it and bought some ridiculously cheap. Turns out that was for a reason, they were full of dust, fungus maybe, I don't know but they were dirty. I decided to clean them myself.
I removed the retaining ring,
there is a thin flat glass in the rear
Then a tapered spacer,
and then to my surprise a tapered piece of glass as the front element.
On the barrel there is a red dot directly above the manufactures name, I will assume this means "Red dot up"
I have no idea how the taper of the glass is oriented in relation to the red dot.
Anyone have this answer for me? and how to insure it stays put in that position while re-assembly.