Originally posted by derekkite Are you sure about that? I would think that unpredictable would be a better description.
I did most of the testing back in the K10d days, but as far as I know it's still holds true for the K5.
As we all know the sensor lays loose behind the shutter until the shutter button is fully pressed, no matter if the SR is on or off or the little hand icon is lit or not. (Unless we are in live view, but that is another case).
So no matter how long you wait with the shutter button half-pressed, the sensor is powerless resting on the bottom of the mirrorbox behind the shutter, it's not swaying around waiting to settle.
Here's a simple test. Turn the camera on without a lens attached, set the focal length to 400mm or so (SR on) and the shutter time to 10 seconds (so you can observe the sensor). Look at the mirrorbox, halfpress, wait a second and press fully. The mirror and shutter pops up, watch the sensor "float" since SR is active.
Do it again, but press quickly without waiting the second needed for SR to activate, and observe the sensor, it's not floating. It's locked and behaves exactly as if SR is turned off.