How does Image Stabilisation work on the Telephoto lenses?

I sort of understand how it works in point and shoot cameras, but I always thought it would have to be a feature built into the camera, not the lens.

I suppose you can try to read the physics of the thing. Personally, I don't know and I don't care. All I know is that when I have my 100-400 L with image stabilzer off at the 400 end, you can see the shake. Switch it to IS and press the focus half way, and - voila - you see the image lock into place!

I will post a couple later..It is unreal the way it helps your photos...I was able to take a pretty decent shot from 200mm at a shutter speed of 1/8. Yeah there is a little tiny bit of blur but the photos still looks sharp..

Cheers...

So it's well worth getting one with IS?

This is a topic that seems to invite controversy. If the lens is long and heavy (70-200 f2.8, 100-400L....) that you will be hand holding I personally believe the IS is necessary, that comment usually brings out the detractors that say it is not true. I base my comments on MY experiences with the 70-200 f2.8 IS, I can't hand hold the lens on a 1.6x camera at 200mm below 1/500 and get an acceptable number of keepers with IS off. Other people may have much steadier hands than me but I have a hard time believing that that they are as much as 3 stops steadier than I am, maybe I am in denial.

If you have a lens like the 70-200, and a tripod, would IS still be necessary?

http://www.canon.com …um/tech/room/f_​index.html
here you can see how IS works

GeForceFX wrote:
http://www.canon.com …um/tech/room/f_​index.html
here you can see how IS works

thanks for that

not if you always will use it with the tripod.

The general opinion is that I.S. will allow you to shoot two stops (shutter) slower than normal and still get a steady image.

In other words, if you were using a focal length of 100mm, you would feel it necessary to shoot with a shutter of 1/100 or faster. With I.S. you could drop down to about 1/25.

---Bob Gross---

It's just that "necessary" is such a strong choice of word,. who's meaning I am nt at all sure you understand if you use it to decribe IS.

By saying it is necessary,. is tantamount to saying it is impossible to take a photo with a 100-400mm IS lens with the IS turned off.

Me I love IS,. and thus can hardly be labled as a "detractor".. but I have a host of lenses that do not have IS, and I spent that last two years doing all my wildlife photography with a 500mm prime that had no IS.

So I have two years and thousands of images that refute the claim that IS is "necessary"

But DAMN it does HELP!!!

A simplified description of how IS works, taken from Canon's lens brochure:

Optical shake is detected by gyro sensors which provide the data necessary to shift the image-stabilizing lens group in parallel to neutralize the shake. This increases the usable shutter speed range by up to 3 full steps for hand-held shooting.

The "gyro" in their explanation is a gyroscope.