IS Questions . . .

[RJSorensen]

I have the new 17-85 EFs lens on the 20D most of the time. This is my first SLR lens with IS features. At what speed(s) or . . . such, should it be either 'turned on' or 'turned off?' I understand that leavening it on all the time can put a drain on the battery. Does one just turn it on and forget it, or use it selectively. I suppose this question could be asked for all of Canon's IS lens.

Can and perhaps will IS cause problems with shots above 1/500 or so? I need to tap the shared experience of the board, if I might. Is there a 'range' that seems to work best for IS . . . and do we know what that is?

My thanks to those whom might be able to enlighten and inspire me.

[DaveG]

I have the new 17-85 EFs lens on the 20D most of the time. This is my first SLR lens with IS features. At what speed(s) or . . . such, should it be either 'turned on' or 'turned off?' I understand that leavening it on all the time can put a drain on the battery. Does one just turn it on and forget it, or use it selectively. I suppose this question could be asked for all of Canon's IS lens.

Can and perhaps will IS cause problems with shots above 1/500 or so? I need to tap the shared experience of the board, if I might. Is there a 'range' that seems to work best for IS . . . and do we know what that is?

My thanks to those whom might be able to enlighten and inspire me.


IS is going to "hold" your camera/lens better all across the range of shuttterspeeds. There is a rule of thumb that says that you shouldn't hand hold a camera below 1/focal length or you will get camera shake. IS should allow you to hand hold with a shutterspeed two to three stops under this. At the higher end you'd be getting the same camera motion stability at 1/500 as handholding it 1/4000. This is all good and I'd encourage you to use IS all of the time. Bring an extra battery if you need to but take advantage of this increased stability.

But at slow shutterspeeds keep in mind what your subjects are doing. You could shoot from a tripod (which is even better than IS) but if the subjects are moving then the image will still be blurry.

[CyberDyneSystems]

I turn it on and forget it... shutter speed plays no part in deciding when to turn it off...

You turn it off whae the IS will impede your shooting.. like tracking a fast moving object, when mounted to a tripod etc...

[RJSorensen]

Thank you Dave and CDS . . . sometimes if you don't know you have to just ask. New fangled things anyway. So far I have had it on one day and off one day and I can't really tell the difference thus far. We will see as time will tell I am sure. Thanks again.

[Adam Hicks]

Well at 1/8000 I wouldn't worry too much about IS :) :) :)

But yeah... just leave it on. It uses a little more battery, but when was the last time one of us ran out of battery!