Originally posted by Khukri Hullo everybody! I'm new in town. One of the reasons I'd say many people - like me - may consider a shift to Pentax (from say Canon/Nikon) would be the K10D's SR. But I see very little discussion on this subject of SR efficiency in hand held shooting vis-a-vis Canon's IS or Nikon's VR lenses - say 300mm IS or equivalent; or equually at the othe rend - macro range with a 100mm lens, hand held. May I request people with experience of both to shed light on this please? Thank you.
Shake reduction in the Pentax K10D and K100D works very well. It's quite easy to do a few quick tests taking shots with SR on and SR off and see the difference.
I have a lot of experience with one implementation of optical image stabilization in Canon cameras - the Powershot S-series, which I owned for years. IS works well in those cameras and it is my experience with those cameras that lead me to buy a Pentax DSLR rather than a Canon or Nikon.
For what it's worth, my experience is that SR in the Pentax K10D and the K100D is as good as the IS I enjoyed in the Canon Powershot S-series cameras. Now, I've never heard anybody claim that in-camera SR on the Pentax cameras (or the other cameras that have in-camera SR) works BETTER than in-the-lens image stabilization. The advantage of in-camera SR is obvious: it saves you lots of money on lenses, because you get SR automatically with every lens you use, including lenses made decades ago.
On the other hand, I have read claims that the in-the-lens image stabilization used by Canon and Nikon is superior to in-the-camera SR. I've heard the claim - but I've never seen any proof, or even any tests, and I've been on the lookout for them. Seems to me that the burden of proof here lies with the Canon/Nikon camp.
I think there is also a fairly obvious physical limit to how good shake reduction or image stabilization of any kind can be. Shake reduction is designed to reduce the effects of very small movements in the camera body - movements so small that the camera sensor can safely assume they are not deliberate. In other words, there's a limit to how good SR can be, and beyond that, nobody's technology can be any better. SR isn't going to help much if you're trying to take a photography while riding a horse! Pentax's SR seems to me to be as good as that limit. I'm open to the possibility that there is a technical advantage to in-the-lens image stabilization - but I am sure it would be a slight advantage. I don't see how Canon's or Nikon's technologies could be any better than that outside limit allows.
My GUESS is this: Canon and/or Nikon have done these tests. They have found that in-the-lens stabilization is indeed better than in-body shake reduction - but only very slightly. They don't tout the results of their tests precisely because it would be a pyrrhic victory: It's better for them to be able to claim superiority without having to prove it, because proving it would require that they reveal how trivial the difference is. And at that point, a lot more people might wake up and realize that paying for IS in the lens over and over and over again is, well, kind of dumb.
Will
P.S. (added later) Ignore what I said above and see instead nosnoop's excellent and informative reply, which follows this message.