Originally posted by Pa. Patriot Why?
Sometimes, that may be the effect desired....
Vibrate violently? Never heard of this. Never experienced it while shooting video handheld.
Examples or references to this?
Why? Try putting a magnifier lens between your hand and the sun, and space it so the sun focuses on your hand.
If that's the desired effect then go for it. If you expect to see a well-formed silhouette of the sun, you will be disappointed. You can try it with the moon also.
If you have not experience sensor vibrations with SR on then you probably are using a wider angle lens (it is more pronounced on telephotos), or you hold the camera either too steady or move it a lot (so the sensor cannot compensate). Try using a long telephoto e.g. 300mm or longer on a tripod with SR on and slightly shake the camera.
Regarding additional noise from a warm sensor, it is simple physics. The sensor heats up while using LV and Pentax shuts it down after a few minutes to protect it. All electronic circuits perform better when they are cooler, hence all the cooling components that go into them (heat sinks, fans, etc.). How much noise is introduced by heat? Probably not much if you use it within the operating parameter. Most likely that's another reason why they shut down the sensor.