Eolake asked: "How effective would you say the K-M stabilization is? Two stops?"
MJ replies: I don't think there's really any hard-and-fast way to judge exactly how many stops any sort of AS/IS/VR will give you. It depends upon a lot of things: the focal length of the lens (longer lenses exaggerate camera motion), the actual type of movement you're asking it to compensate for (i.e., vertical, horizontal, moving the whole camera or just wiggling one part of it, yaw, twist, whatever), and how steady you are with the camera anyway. For me, how much coffee I've had that day makes a noticeable difference too.
It's certainly good as a parlor trick. For instance, in the above two shots, the camera was set exactly the same way, and I was purposely bobbing the end of the lens up and down (people always grin when I do this, as my friend Barb H. is doing in the first of these shots). She leaned forward and over a bit before I took the second shot, so the background is slightly different, but the only other thing that differs between the two shots is that in the first one AS is switched off, and in the second one AS is switched on.
This was not a controlled test—I was simply showing her the feature—but I've made these JPEGs pretty large so you can inspect the difference more closely. Just click on either picture to see the larger versions. You'll notice that the "AS on" shot, the bottom one, is not perfectly sharp; but then again, as I say, I was deliberately moving the camera pretty violently when I took both shots, and the light was pretty low—it was indoors on a midwinter day.
In any event, AS/IS/VR, or whatever they want to call it, is something I'm personally totally sold on. It has proven more useful to me in my own photography than almost any camera innovation I can think of in my entire lifetime; that includes autofocus, built-in motor drives, "Matrix" or multi-segment evaluative metering...even digital capture itself! All those things (and a dozen other innovations I've watched go by) are useful and meaningful advances in varying degrees too. But day in, day out, image stabilization is more useful to me than any other single technological advancement. Bravo to the Canon scientists who (I believe) were the ones who first came up with it.
Posted by: MIKE JOHNSTON