> Someone mentioned a few years back there were several small screws
> on the lens that could be tightened.
I have used a couple A 70-210/4's quite a bit over time, and one of
them (due to much use in very dusty conditions, including wind-blown
sand) actually started to develop a "gritty" feel when it was
focused and/or zoomed. (Fortunately, there was very little internal
dust in the optical path itself.) I took off the rubber sleeve over
the focus/zoom ring, and proceeded to remove as much of the "grit"
as I could reach {with cotton swabs for the more accessible places
and pieces of sticky tape for the thinner crevices). I do remember
there being some white plastic screws (nylon, I am guessing,
although I suppose they might have been teflon) under the sleeve.
Perhaps those are the screws that could be tightened as necessary
(although I had no desire to "stiffen up" the focus/zoom action, so
I didn't try adjusting them - I just wanted to get rid of the
"grittiness", which I did succeed at, by the way).
Fred
