Originally posted by stormcloud think its generally accepted that at long focal lengths the sensor shift shake reduction cant cope where lens stablisation can - it also stablises the viewfinder too which can be useful...
So here's a question for anyone out there who's tried a "stabilized" Sigma lens on a Pentax with sensor stabilization built-in: Is there any way to turn off the lens's stabilization??
Reason I ask is:
1) On the K7, the sensor stabilization is disabled when you choose Mirror-up or Exposure bracketing or remote trigger or HDR, undoubtedly because it assumes you're using a tripod. Personally I find that assumption extremely frustrating, but presumably Pentax has found that the sensor stabilization can actually *introduce* motion blur. Thus, it's probably fair to assume that Sigma's in-lens stabilization would have the same unfortunate side-effect, and you'd need to turn it off when using a tripod.
2) The lens has no way to know whether you have a 2X teleconverter on there, which certainly would affect the effective focal length and thus the amount of stabilization needed. So that's another reason it might be beneficial to be able to turn off the lens's stabilzation.
3) If you switch lenses often, it would be a pain to have to remember to turn off Pentax's sensor stabilization every time you mount a Sigma lens with in-lens stabilization. (I'm assuming that it would be a blurry disaster to keep BOTH stabilization systems enabled. Sigma says vaguely, "For Sony and Pentax mount, the built-in OS function of this lens can be used even if the camera body is equipped with an image sensor shift anti-shake system."
So, to me, the Sigma in-lens stabilization sounds like a royal pain in the butt.