Most people tend to think of image stabilization as being mainly for telephoto lenses. While it's true that their longer focal lengths tend to magnify the effects of camera shake, image stabilization can provde a very useful assist at wider angle focal lengths as well; anyone who's ever tried to blur the image of a waterfall, while keeping the surrounding landsape tack-sharp knows exactly what I'm talking about.
The Canon 55-250mm image stabilization system is excellent at the 55mm focal length. We see four solid stops of hand-holding improvement: it's possible to get rock-solid images at speeds as slow as 1/4 of a second:
 |
| Mouse over this chart to show results with IS activated. |
At 250mm, we didn't see a great improvement, only about a half a stop:
 |
| Mouse over this chart to show results with IS activated. |
We tried the same test again using the camera's live-view functionality, and were quite surprised to note in this mode we see about one and half stops of improvement. It's been speculated that there is some interference between the mirror slap or the shutter action and the image stabilization system; either way, it's not terribly amazing:
 |
| Mouse over this chart to show results with IS activated. |
IS systems tend to provide more benefit to less-stable shooters than very steady ones, so most users will see the same or greater amounts of shake reduction as we measured here. You can read more about our IS test methodology here: SLRgear IS Test Methodology, v2.
