Originally posted by photoptimist It's not BS. In fact the primary correction is the use of 2 linear axes of up-down/left-right motion of the sensor to correct for two rotational axis disturbances (pitch and yaw).
How does the up/dow/left/right movement compensate for pitch and yaw? It seems like only moving within the sensor plane would not be sufficient for that, in that there would be some tilting of the plane of focus relative to the sensor. Or is the idea that it is minimal enough that in most cases it wouldn't affect the focus and focal plane? Now that I think of it, I have occasionally seen what looks like weird plane-of-focus changes from one frame to another when I have taken two in quick succession.
Quote: It's only roll axis motion of the camera that provokes an identical-but-opposite roll axis correction by the sensor.
What changes in going from the original 2 or 3 axis SR to full 5 axis is that an additional two axes of linear motion of the camera are corrected with additional amounts of linear motion of sensor which depends on optical magnification ratio (which depends on both focal length and distance).
Tilting the sensor, although it sounds cool, is almost pointless because it would do nothing to correct motion blur except under the most extreme motions.
In the older Pentax SR diagrams, they show only the linear motion of the sensor, like for the K-70:
With the newer 5-axis SR II, they use a different style of diagram showing the pitch, yaw, and roll, like the K-1:
There's a slight amount of explanation here comparing Sony vs. Olympus, and there is a better version of the K-1 style diagram that makes the pitch & yaw effects more obvious:
A Comparison of How Olympus and Sony's 5 Axis Stabilization Work
Is Pentax's shake reduction completely independent of Sony & Olympus? Or do they share technology?