Rudy Winston
Rudy Winston

Rudy Winston has over 17 years experience with Canon USA's Pro Products team, and has been responsible during that time for training Canon's staff on new products, creating presentations for customers and dealers, numerous writing projects, and providing technical assistance to professional and amateur photographers.

Revisiting the benefits of Image Stabilization

February 25, 2014

There’s little I’d change about my position at Canon USA, other than wishing it allowed more time to go out and do what I love most: shooting pictures. Sometimes, opportunities do present themselves, and they’re often a reminder of how fortunate we as photographers are to be living and working with 21st century technology.

I’ve had the privilege of working in the past with the Canon EF 70–200mm f/2.8L IS II lens, and know from experience what a great lens it is. But one of its greatest assets can sometimes be overlooked: its 4-stop Image Stabilization capability. I wasn’t even thinking of it when I packed an EF 2x III tele extender and that lens for a recent trip to a zoo — but it quickly showed its worth.

Adding a 2x Extender immediately changes that lens into (effectively) a 140–400mm f/5.6 zoom lens, without changing its minimum focus distance. But it does change the need for steadiness. Normally, most users would probably agree that at 200mm, without stabilization, about 1/250th or so is a reasonably slow and safe shutter speed for reliable hand-holding — without the extender. But with the 2x Extender in place, you’d normally expect to need around 1/500th, give or take, to ensure consistent frame-to-frame sharpness at the effective 400mm max. focal length.

Here’s a place where Image Stabilization changes the shooting experience. Shots at shutter speeds as slow as 1/80th, in shade, become completely possible at an effective 400mm.

Photo by Rudy Winston
The need for shadow detail leaves two choices: raise ISOs or work at slower shutter speeds — the lens is already wide-open. Here, a shutter speed of 1/80th second, hand-held, was possible at 400mm (equivalent) with the 2x Extender and EF 70-200mm f/2.8L IS II lens.


A common concern when working with Extenders is that, while they reduce the effective maximum aperture of a lens, they don’t similarly reduce depth-of-field — in other words, in essence, that EF 70–200mm f/2.8L IS II zoom with a 2x Extender has depth-of-field very similar to that of an EF 400mm f/2.8 lens when used wide-open. Accordingly, there are times when stopping the aperture down becomes desirable, if not downright necessary, to extend the tissue-thin depth-of-field to something useful.

Once again, Image Stabilization to the rescue.

Photo by Rudy Winston

In this shot (taken through a fence, incidentally!), stopping down to f/11 at ISO 400 meant a shutter speed of 1/125th… risky business in a hand-held shot at 400mm, normally. But I.S. again takes all the worry out of this. Preset f/11 to get a little more sharpness throughout the bird’s body (Av mode with an EOS-1D X), back-button AF using an upper AF point and zero exposure compensation. With I.S. active, the view when composing and focusing is steady and stable, and the final shot is more than acceptably sharp.

Photo by Rudy Winston
Detail of the previous shot, taken hand-held at 1/125th of a second. Image Stabilization proves its worth, especially as focal lengths get longer, and speeds begin to drop.
Another forgotten I.S. advantage

Image Stabilization isn’t just a benefit at slow shutter speeds when hand-holding, however. It can actually make your AI Servo AF better — even at the fastest shutter speeds.

I’ll switch gears and look back at another shot taken with an EF Extender, in this case, using the superb EF 200mm f/2.0L IS lens and an EF 1.4x III Extender at a hockey game. Effectively, this hand-held combination is a 280mm f/2.8 lens, shot wide-open in available light. In action situations, Image Stabilization provides a much more stable view in the finder, even when rapidly moving the camera to follow an erratically moving subject. But beyond that — and many sports photographers don’t think of this — if I.S. is active, the autofocus sensor gets the same stable, clear view of the subject that you would through the viewfinder. Whether working hand-held, as I was in this shot, or from a monopod, the AF system gets a better look at the subject and has an advantage in reading detail and reacting instantly to it during a high-speed, continuous shooting sequence. The benefit? Even greater likelihood of consistently sharp frames, throughout a sequence.

Photo by Rudy Winston
This isn’t a slow-speed shot, but Image Stabilization can actually help your AF system get a steadier, more stable view of your subject in-between each frame of a high-speed sequence. Accordingly, it can sometimes increase your percentage of sharp action pictures, even at the fastest shutter speeds.


A lot of sports, wildlife and similar long-lens shooters assume that if they’re working at fast shutter speeds — 1/500th, 1/1000th and up — that they don’t get any benefit from I.S. Not entirely true, according to Canon’s engineers.

So don’t think of Image Stabilization as strictly a tool for candlelight shots with standard focal length lenses… adding a tele extender multiplies not only your effective focal length, but your need for steadiness. If the lens you’re using with an Extender does have I.S., simply switching it on can bring numerous benefits, and the potential of sharper pictures.

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