Dodgy Pentax
 

I've got a couple of Pentax DSLRs and rarely use them for video - so this applies to a K5, used for stills only.

It's suddenly behaving oddly - you take a picture, and on the screen, after the usual few second wait, is a decently exposed picture - in aperture or shutter priority mode. Then you take a series of images, and while it works fine in low light, sunlight seems to be causing a problem - a few will be correctly exposed, then four or five will be vastly over, then it goes back to normal. I'd estimate 25% of the images I took were over-exposed, outside the ability of photoshop to recover.

Anyone have any ideas what is going on?