SDM type Auto Focus motor quit working and known to be a problem
B. Breshears, Amazon
21 March 2009
Summary: I'm usually reluctant to give low ratings and write negative reviews. Unfortunately and to Pentax's shame, I have to warn users about this Pentax lens with the built-in SDM drive motor for the auto focus. BTW, I like Pentax cameras and lenses and still use them, but they have problems with these lenses. My 2-star rating would have been lower if the optical quality hadn't been as good.