Originally posted by pakuchn
All Pentax lenses that are currently in production are autofocus lenses. So, all the lenses on that site are AF lenses.
Any lens that is called F, FA, DA or D FA is an autofocus lens. Others are not. The F-series are the first generation of Pentax AF lenses, for film cameras. None are being made, but if you buy one used, it will work on a Pentax dslr, with no problems or limitations.
The DA lenses are specifically designed for the APS-C sensor used in all Pentax dslrs. They will physically mount and function on a film autofocus camera, but they may or may not cast a large enough image to fill the 35mm film frame. The FA and D FA lenses do not have this limitation.