Thanks for this opportunity. I did a dust check on my K-7, and it shows dust on the sensor that won't come completely off. I can't see it on any of my pictures at 300X, but it bothers me that I know it's there.
Also, I was shooting a rapidly approaching race car in Tv mode at 1/6000 shutter on a cloudy day, and I let the aperture float. When I got home, I could see that focus was sharpest on the headlights on one, and on the windshield on the next. On some, nothing was in focus! Obviously the autofocus is too slow to keep up.
I've e-mailed Pentax for a new camera to replace this one. I think I deserve it because I write a lot on this blog. But, I'm considering changing over to Canon because the AF is so much faster. I'm letting everyone know about my decision on this Pentax forum because I like to draw attention to myself, and I like to pretend someone will give a hoot.