Originally posted by séamuis the 70-210 is an excellent lens. it sees more use than almost any of my lenses. that push/pull zoom might have been a standard at that time (just about everyone had a 70-210 with this design) but pentax really got it right. after some practice, you can zoom and focus extremely quickly. they are prone to 'zoom creep' but man this is one hell of a lens.
I have to agree with séamuis on the A 70-210/4 - "pentax really got it right". Sharp, contrasty, well built.
As for the dreaded "zoom creep" (especially in a well-used lens) (a common grumble about one-touch zooms especially), well, this would only be noticeable if you were using the lens on a tripod pointed downward or upward - more-or-less level use would never exhibit this. Furthermore, some of the ability to "zoom and focus extremely quickly" depends on a zoom/focus ring that is ~not~ too tight.
I have never, ever used this lens on a tripod myself (pointing in any direction), so I have not once ever experienced the trauma of "lens creep" - <g>.
It is not a perfect lens, of course (it is, after all, a zoom). It's so-called "macro" function (as in most - but not all - so-called "macro zooms") is a bit marginal. The built-in sliding lens hood is only a little better than nothing (but you can carry a longer screw-in hood, of course).
The A 70-210/4 is a solid, well built, optically quite good telephoto zoom, well worth owning. And, at the modest prices they sometimes go for nowadays, it's a "best buy" in my mind, and a sweet lens for use on a body such as a Super Program.