Originally posted by m42man I hope Class A will revisit this thread...
Thanks a lot for the original compliment and the invitation to repost.
Originally posted by Canada_Rockies I believe you will find that this does not address any movement in the Z axis (nearer to/further from the subject)...
One has to distinguish between rotational movement (yaw, pitch, roll) and translational movement (left/right, up/down, forward/backward).
The K-7/K-5 only has sensors for rotational movement. That's fine because at larger distances camera shake that is of rotational nature will dominate image blur. Think of a light point painted by a laser pointer on a distant wall. Any yaw and pitch movement will be very visible whereas any translational movement will be negligible in comparison.
Yaw and pitch rotational shake will be compensated by shifting the sensor within its plane (compensating the shift of the image -> think of the shift of the dot painted by the laser pointer on the far away wall) and roll rotational shake will be compensated via rotating the sensor in its plane.
For macro work there is a different story. Here the translational shake dominates and Pentax cameras cannot compensate for it because they don't have sensors for detecting translational shake.
There are a few lens-stabilisation systems for macro lenses which are optimised for close focus distances. I'm assuming such lenses can sense translational shake. It would be great if future Pentax cameras were fitted with further sensors so that SR would be useful for macro work as well.