The Canon EOS Digital Rebel XS/1000D Companion

Handheld Shooting and Shutter Speed

No matter which mechanism you use, once you start fiddling with shutter speed, you have to be very careful about the shutter speed you choose. Pick one too low, and you'll run the risk of getting blurry images due to camera shake. The problem is simply that it's impossible to hold a camera perfectly still. As animals, we don't stand still, we sway—it's a necessary part of balancing on two legs. When you throw in breathing and a beating heart and possible windy conditions, holding a couple pounds of camera perfectly still becomes impossible.

So, what's the slowest shutter speed that you can use when shooting handheld? That depends on your lens and on the focal length you're shooting at.

With a longer focal length—when an image is greatly magnified and has a very narrow field of view—holding the camera steady is much more difficult, because any tiny movement or vibration is much more noticeable than at wide angles, when you have less magnification and a broader field of view.

The rule of thumb is that the slowest shutter speed you should use is 1/focal length. So, if you're shooting with a 100mm lens, you shouldn't use a shutter speed that's less than 1/100th of a second. But, as you learned in Chapter 4, the effective focal length of any lens that you put on the Rebel XS is the lens focal length multiplied by 1.6. So, if you set your zoom lens to 100mm, the slowest shutter speed you should use is actually 1/160th of a second, or 100 × 1.6. ...