[Moved thread from Pentax Articles]
The K30 (but not the K5) definitely does AF in video mode. But not continuously.
From the in-depth review:
Quote: Autofocus
Autofocus can be used before and during recording. However, the feature that a lot of users are looking for—continuous AF during recording—is not available here. While recording, you can press the AF/AE-L button to force the camera to refocus, but once it locks onto a target it stops and you have to press it again to refocus a second time, etc. This is the same regardless of which Contrast AF mode you've selected, Face Detection and Tracking included.
More Pentax news at:
Pentax K-30 Camera Review - Introduction - PentaxForums.com I would still try and use manual focus if possible. Much quieter and smoother, more professional.