at what shutter speed you turn IS off?

[Danielle]

*sighs* the only time you really should be turning it off is if your shooting fast moving objects/people or on a tripod. And that depends what lens in some cases. IS 3 mode is for fast moving objects for example but doesn't occur on anything but big expensive glass.

The hum in the lens from the IS doesn't get louder by the way!

[PeterJ]

Another reason to switch it off aside from the potential effect on AF speed/accuracy is that some wildlife reacts to the sound of it.

   Wow!  Really??  So does this mean that if you turn off the IS, you only get one shot when the much louder SLR Actuation scares off the wildlife?

Actually that wouldn't suprise me for a lot of animals, for example from Wikipedia "Bats that can detect 200 kHz cannot hear very well below 10 kHz". Mice are shown at 1 to 70 kHz and there are many other examples at http://en.wikipedia.org/wiki/Hearing_range. According to the following page the USM motor runs at about 30kHz:

http://cpn.canon-europe.com/content/education/technical/usmlens_technology.do

Note sure what the frequency components of the shutter noise are, but I'm pretty sure the loudest components would all be below 1KHz.

[bdunbar79]

*sighs* the only time you really should be turning it off is if your shooting fast moving objects/people or on a tripod. And that depends what lens in some cases. IS 3 mode is for fast moving objects for example but doesn't occur on anything but big expensive glass.

The hum in the lens from the IS doesn't get louder by the way!

What if your lens doesn't have IS?  I guess you'd still be right, you can't turn it off.

[Hillsilly]

IS - one of the topics where it seems like no one has any idea what they're talking about.

I can't even remember the last time I turned IS off.  Yet, I've read numerous times that you should turn it off when not needed.  For example...

http://www.bythom.com/nikon-vr.htm

Maybe Canon's system is better.  Maybe some of my shots would be better without it.  Who knows?

If there are benefits with keeping it off in some cases, maybe there is an argument for a camera setting that allows you to disable IS automatically under certain conditions (eg above a certain shutter speed).

[serendipidy]

I paid a lot of money for that IS...so I leave it on all the time

[sanj]

Another reason to switch it off aside from the potential effect on AF speed/accuracy is that some wildlife reacts to the sound of it.

Never felt this way in the last five years of wildlife photography with IS. I had non lS lenses for 15 years before that and no wildlife got distracted by other sounds in my vehicle (lenses bumping on to metal etc.)

[BL]

i've never once remembered to turn it off, on countless long exposures mounted on a tripod, on both 70-200 II and 100 L

never experienced any decrease in sharpness

[sanj]

Another reason to switch it off aside from the potential effect on AF speed/accuracy is that some wildlife reacts to the sound of it.

   Wow!  Really??  So does this mean that if you turn off the IS, you only get one shot when the much louder SLR Actuation scares off the wildlife?

Well said!

[serendipidy]

I'm usually so far away they can't hear it

[Studio1930]

I'm done eating my popcorn now so I'll weigh in on this topic.

IS is like Canon vs Nikon.  Everyone has a different opinion so the best thing to do is try YOUR camera with YOUR lens with YOUR eyes and YOUR steady (or not) hands and use IS all of the time and then none of the time to see which shots look better.

For me, I leave it on all of the time except when on a tripod (rare).  I even leave it on when using a monopod but I use mode 2 (please don't start arguments about mode 2 vs monopods vs panning).   

Now everyone go out and start shooting. 

[Northstar]

I'm done eating my popcorn now so I'll weigh in on this topic.

IS is like Canon vs Nikon.  Everyone has a different opinion so the best thing to do is try YOUR camera with YOUR lens with YOUR eyes and YOUR steady (or not) hands and use IS all of the time and then none of the time to see which shots look better.

For me, I leave it on all of the time except when on a tripod (rare).  I even leave it on when using a monopod but I use mode 2 (please don't start arguments about mode 2 vs monopods vs panning).   

Now everyone go out and start shooting. 

mode 2 on a monopod....c'mon, you gotta be kidding me???    

I did watch a youtube video recently that had the team photographer for the (my memory fails me but I believe it was Tampa Bay Rays (Major League Baseball) and he said that he and his team turn IS off because they thing the AF is faster. (shooting Canon tele's and super tele's)

anyway...this is a subject that I've read alot about recently, and it's starting to play "mind tricks" on me now.  for example, I shot sports the other night and I had way too many oof shots for my liking...so I started thinking, maybe it's the IS.

as charlie brown would say....aaughhhh!

[brad goda]

hmm interesting ....
not pertaining to shutter speed but I do turn off IS when shooting critically framed shots using tripod and lights... like when shooting 2D art work... the framing gets tight and with IS on there is micro "FLOAT" where the image will shift a bit when stabilized... since no need for IS on these types of work we just turn it off... at first I thought who is moving the tripod but yes its the IS activating and settling into position...  IS has come a long long way... the first canon IS zooms in the 90s didnt quite "stabilize" and would float... i used it on a golf tournament and it got me sick... like boat sick... I thought... this will never take... 
anyway cool to read the posts ... sometimes gotta clear your mind and ego to learn new things.
Mahalo

[FTb-n]

As stated earlier in this thread (see page 2) IS does not slow the AF system and will likely help it.  Look for the Chuck Westfall quote (HT. privatebydesign).  This makes sense, particularly for moving objects.  The steadier the image, the easier to focus.

Mine is on at all times for all IS lenses in my sig line below.  It is curious though that experiences with IS, particularly with battery drain, must be dependant upon the lens.  I think my biggest power hungry lens would be my 70-200 f2.8L Mk2 and I don't think there's a noticeable drain using IS on this lens.  But, maybe there is with the really big boys.

[Edit: Just realized that I only have two IS lenses in my sig line.  Others include the 18-135 (non-STM), 17-85, 70-300 (non-L).]

[florianbieler.de]

I actually never cared too much about IS, really only turning it off when on a tripod.

[mrsfotografie]

I leave it on or select mode 2 for motorsports. Rather annoyingly Ive accidentally switched IS off several times without knowing it while handling my 70-200 IS. This happened quite often on the MkI version of this lens and I need to monitor this behavior on the MkII. If it occurs again I will probably tape a small piece of toothpick in the gap next to the switch to keep it on.