frayne wrote in post #17933949
I've noticed that when I turn off the IS on my 70-200 and 100-44 L lenses I seem to get many more shots that are in focus. Of course this is in good light and faster shutter speeds usually above 1/500 sec. Just wonder what others might think or have experienced. In the future I don't think I am going to be paying for the additional IS feature.
If you are getting a better "keeper" rate with IS turned off, you are doing something wrong.
I've been using a bunch of different IS lenses for 15 years... All Canon (no Tamron VR or Sigma OS).
I virtually never turn IS off on any lens and have made 100s of thousands of images with it.
There are a few IS lenses that require it be turned off, when the lens is solidly locked down on a tripod, so that there is no movement what-so-ever. In this situation, a few IS lenses can go into sort of a feedback loop where IS actually causes "image shake", rather than preventing it. The Canon lenses that I know for certain do this are 24-105L, 28-135, 75-300 (IS version discontinued years ago), 300/4L and the original 100-400L.
Most other IS lenses will turn off IS automatically when there is no movement. This includes all the 70-200s with IS, as well as all 200/2, 300/2.8, 400/4, 400/2.8, 500/4, 600/4, 800/5.6, 200-400, 100-400 II and more with IS.
All the IS lens manuals recommend turning it off on a tripod. However, according to Canon USA tech guru Chuck Westfall, for the large part this merely simply to save a little battery power, since some is needed to run IS. (However, I have to say I see little difference using identical cameras alongside each other... one with an IS lens and the other with a non-IS. IMO, IS actually uses very little power. Especially lenses that turn it off automatically when not needed.) Chuck also provided the list of IS lenses above, that need IS turned off on a tripod.
I use two of the lenses on that list a lot (28-135 and 300/4). However, both these I most commonly use handheld, occasionally on a monopod, almost never on a tripod. So I can't recall the last time I turned off IS even on those.
Canon has added IS to a lot of lenses in recent years, including many really affordable ones.... Some of these newer lenses might also need manually turned off, if locked down so that there is no camera shake movement what-so-ever. You'll know quickly if IS needs to be turned off... because you'll see the IS causing rapid, jumpy movements in the viewfinder. This won't do any harm to camera or lens, so you can simply turn it off then. (Don't confuse this with a slower "image drift", which is common with IS lenses. This doesn't effect image sharpness at all.)
I completely disagree that Canon IS "slows down" autofocus. In fact, personally I think Canon IS helps AF perform faster and more accurately. If you think about it, it makes sense that a stabilized object would be easier for the AF system to lock onto and track. (Note: I hear a lot of Nikon shooters say that they think VC slows AF on their cameras... and there may be some evidence to support that. But I also wonder if some of that is residual "sour grapes", because Nikon was very slow to adopt stabilization, many years behind Canon.)
IS also can be helpful when tracking moving subjects, because it helps stabilize the image you see in the viewfinder. This is much like IS on binoculars and can be helpful at times. This is only true of systems that use in-lens stabilization (Canon and Nikon, and a few Sony lenses). DSLR system that instead use in-camera stabilization do not enjoy this added benefit (Olympus, Pentax, most Sony... except for a few DSLRs with electronic viewfinders).
To me, IS is generally worth the extra cost on any lens 70mm or longer. It is especially valuable on telephotos. It's also nice to have (can't hurt!) on shorter focal lenghts, but IMO less necessary since they're relatively easy to handhold even without it. Still, I'd always rather have a lens with IS, than one without it. I certainly wouldn't turn down a shorter focal length that has it... but am more likely to pay extra for a telephoto with IS.
One lens I haven't bothered to upgrade to IS is my Canon 100/2.8 USM macro. That's because IS on macro lenses is of limited assistance at higher magnifications. The 100L probably has the best IS on any macro lens, it's a special hybrid version developed just for the macro lens... However even it only gives about one stop of assistance at the lens' highest 1:1 magnification. (This is better than some other brand stabilized lenses that give almost no assistance at 1:1). I don't really need IS on a macro, anyway, since it I'm more often using them on a tripod or monopod, or using flash (which also freezes movement). Someone who uses a macro lens more often for lower-magnification close-ups or non-macro purposes as a short or moderate telephoto, might find IS more useful than me.
But I really appreciate IS on a bunch of other lenses.... and rarely turn it off. In fact it was one of the top reasons I switched to the Canon system in 2001.
I have not used Sigma OS, Tamron VC or Nikon VR enough to compare. All the above pertains only to Canon IS. Those other manufacturers' systems are likely to differ from Canon and each other in some ways, because they all have to avoid patent infringements and no doubt each has engineered their own methods of stabilization.