P510 - the very first impression and a video tip
Mine seems to occur at the start of any zoom, but just for an instant. When shooting stills, the only time I could see it being a problem was if you were shooting multiple shots while zooming. But during video, it is captured and noticeable.
Perhaps that is the way all digital still cameras capture video... this is the first one I've had that captures "real" video. The old point and shoot I replaced with the 510 did very low rez video... I don't remember the focus thing happening but the video was so bad, I may not have noticed.
It's not a huge problem since the zoom itself is pretty abrupt anyway... certainly not as smooth, slow, or controllable as my Canon HFG10. Any video I do shoot will probably be editing in Premiere and the messy bits removed.
I do like the fact that the monitor zooms fully when setting focus although I miss a physical ring... both the manual focus control on the back of the body or (if you have it setup) the side of the lens are clunky and slow, imo.