Originally posted by blende8 I would never buy a lens with wobbling elements.
Never, ever.
They are out there already in various forms -- they seem to work great, probably better than Pentax's in-camera version but at much greater cost and weight. It sounds like where it is available for a Pentax lens (like the newest Bigma), the majority prefer the OS stabilization of the lens to the in-body version. Maybe because you can see the difference in the optical viewfinder. But it would be nice for handheld macro. Wobbling elements are nothing to fear, just like wobbling sensors aren't. I don't know exactly how they work, but probably just like a bellows lens (moving elements have always been with us) -- I imagine there is just one element that is allowed to move laterally, shifting the image around a bit, pretty much just like the sensor shift.
But it also seems like Pentax should just add the extra sensors it needs to the body so it could handle this with the sensor also. (As I understand it, the Pentax sensors are only currently only picking up rotational movements.)