Stabilizing the Situation
If you purchased your camera with one of the new Image Stabilizer (IS) lenses, you already own a great tool to squeeze two stops of exposure out of your camera when shooting without a tripod (Figure 7.5). Typically, the average person can handhold their camera down to about 1/60 of a second before blurriness results due to hand shake. As the length of the lens is increased (or zoomed), the ability to handhold at slow shutter speeds (1/60 and slower) and still get sharp images is further reduced.
Figure 7.5. The IS feature on your lens could mean the difference between a sharp image and one that is full of noise from a high ISO.
Canon IS lenses contain small gyro sensors and servo-actuated optical elements that correct for camera shake and stabilize the image. The IS function is so good that it is possible to improve your handheld photography by two to four stops, meaning that if you are pretty solid at a shutter speed of 1/60, the IS feature lets you shoot at 1/15 and possibly even 1/8 of a second (Figures 7.6 and 7.7).
