The A35-70 f/3.5-4.5 is the same optical formula as the F35-70/3.5-4.5. I found one of the latter in "as new" condition for $45. It's a very good lens, a bargain at that price. Focuses well manually, contrasty/sharp/good rendering, and is very compact and light.
Godfrey
Same optical formula indeed but the difference in performance for these two lenses are so different that I think Pentax modified the optics for the F lens.
Andre
