I bought new an 80 to 200 2.8 lens 12 or so years ago. It has been a work horse on my F100 then my D70s and then d300. Working flawlessly. Right now if I put it on my D300 it will not take an image or focus. However it still works flawlessly on my D70s. It throws a code that says my ap ring isn't locked but it is?? Any ideas?