For the life of me, I can't remember what the letters UD stand for - can someone help please? Thanks in advance, Ron
Don't know if you ever got your answer here's a link with a good bit of info on lenses:
If I read it correctly the UD indicates 11 elements in the lens.
Thanks Joe - I was trying to buy a 20mm UD but lost out
Good morning, Ron;
There was hope that I would find my Nippon Kogaku K. K. reference books, but that has not happened yet with the other activities here. All that I can remember right now is that the Letter "U" was their designation for Eleven (11) Glass Elements in the lens design, but I cannot recall right now the significance of the Letter "D." This was a fairly early Retro-Focus Design NIKKOR lens.
Enjoy; Ralph, Latte Land, Washington
I bought a 20mm NIKKOR in '71 while an Army still photographer. Still using my favoritest lens!