when to us IS?

I have a Canon 28-135 USM with image stabilization. I've just been turning on IS when I've got a slow shutter speed (<1/60). Is that how I should use it or should I just have it on all the time? It seems to slow focus down a bit when I have it on. Is there a downside to keeping it on?

2k2s

I don't have a whole lot of experience with these lenses, but that's basically the best way - turn it on only when you need it. 1/60 is a good starting point or maybe even a little faster on the longer end of the lens. A good starting point for minimum hand-held shutter speeds is the reciprocal of the focal length (1/60 for a 60mm lens, etc). Slower than that you could use a tripod or IS to some degree. Once you practice with handholding you can probably go slower than that without IS too, but stay off the coffee (my downfall!).

IS takes battery power to operate, so the battery in your camera won't last as long if it's on all the time. With the Nikon VR lenses (may be the same with Canon), they say it's best to focus on the subject and give it a second to activate before pressing the shutter release. That can slow you down if you don't need the IS. Of course, IS will only stop camera shake, not a moving subject.

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Originally Posted by 2kids2shoot

I have a Canon 28-135 USM with image stabilization. I've just been turning on IS when I've got a slow shutter speed (<1/60). Is that how I should use it or should I just have it on all the time? It seems to slow focus down a bit when I have it on. Is there a downside to keeping it on?

2k2s

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In my opinion, you should always have it on. It won't hurt anything, and it provides a solid, steady image in the viewfinder. When I had this particular lens, I never turned IS off. My other IS lens is a 300 f/4 L IS, and I always leave it on too. Really, I can't think of a reason to turn it off, except for maybe the miniscule amount of energy that IS uses. That is negligible, however.

Only turn it on when you need it. It tends to slow down AF by just a bit when it's on. When you need uit depends on how steady you are and what focal lengths you shoot at.

...I have a dumb and silly question, but I've needed to know when I'm out shooting and I always get mixed up...


Is the little line "off" and the open circle "on"? Or is it the other way around?

1 (the line) is on

0 (the circle) is off

Simon

Thanks everyone for your responses - I appreciate your time!

What I interpret from your reponses is it's more or less up to me. I suspect I'll leave it on in situations where I'm shooting slower speeds and where I don't need real fast focusing response (eg landscape or macro).

2k2s

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Originally Posted by 2kids2shoot

What I interpret from your reponses is it's more or less up to me.

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Exactly. It's a tool - use it when you need it.

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Originally Posted by 2kids2shoot

Thanks everyone for your responses - I appreciate your time!

What I interpret from your reponses is it's more or less up to me. I suspect I'll leave it on in situations where I'm shooting slower speeds and where I don't need real fast focusing response (eg landscape or macro).

2k2s

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That sounds like a good plan. However, I question the assertion that IS slows down focusing speed. This seems unlikely to me, and is something I have never observed in my own photography, and after having taken hundreds of photos of fast moving sports subjects with various IS lenses. I would appreciate it if someone could post a link to some empirical evidence to substantiate this assertion. Thanks.

Quote:

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Originally Posted by 2kids2shoot

I have a Canon 28-135 USM with image stabilization. I've just been turning on IS when I've got a slow shutter speed (<1/60). Is that how I should use it or should I just have it on all the time? It seems to slow focus down a bit when I have it on. Is there a downside to keeping it on?

2k2s

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I use to turn IS on only when I needed it, but it's amazing with longer focal lengths how often I needed it. On my 70-200 f2.8L IS, I keep it on all the time so I won't have to stop and fumble around to turn it when the shutter falls below the 1/focal length rule. IS only uses energy when the shutter is depressed so it doesn't actually use up that much energy, and I always pack at least one spare battery.
Here's a sample with your lens- 1/6 sec @ f32
<img src = "http://gallery.photo.net/photo/939510-lg.jpg">

I leave the IS on for both my IS lenses. I have never seen any AF slowdown at all. Also, IS does not affect battery life. According to Canon, IS is only drawing power when the shutter is pressed. That is hardly a lot of time to drain the juice.

It seemed like it was taking longer to me, but I just got the camera and lens and it's my first autofocus SLR (calling the G2 autofocus would be misleading ;D). Could easily be me just getting used to it. Come to think of it, when I had it on occasionally the other day to take some pics at a recital I didn't notice when it was on or off.

Thanks for setting me straight on that. I'm not too worried about battery consumption - I've never had a problem with that yet (*knock knock*).

Lionheart - beautiful pic.

I'll just turn on my IS now....

I was looking thru my camera manuals for something else and I took a quick look thru the lens manual. In there it states that the IS takes about 1 sec to stabilize. Since that's slower than shutter lag I suppose I could see where it might make a difference (I don't know if the camera waits for IS to stabilize or not). Could also be engineer CYA (I am one so I know about that!) I doesn't sound like IS has been a problem for people who have those lenses so I'm not going to worrry about it anymore!