20mm F3.5 UD lens

For the life of me, I can't remember what the letters UD stand for - can someone help please? Thanks in advance, Ron

Ron,

Don't know if you ever got your answer here's a link with a good bit of info on lenses:

http://en.wikipedia.org/wiki/Nikon_lenses

If I read it correctly the UD indicates 11 elements in the lens.

ja

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

Thanks Ralph!