Excerpt from Scott Kelby's Digital Photography book, Chapter 3, The Truth About Lenses—When Should You Use Fast Lenses?
When Should You Use Ultra-Fast Lenses?
For indoor shots without flash—for example, in a church, museum, theater, or anywhere else where you cannot use a flash or tripod—you need a very fast lens. A lens whose aperture can be set very wide, such as f/1.8 or, even better, f/1.4. The lower the number, the less light you need to shoot without a tripod.
Why is this so important? When you shoot in a dark setting, your camera needs a slow shutter speed to gather enough light for the photograph. As long as your camera is perfectly still on a tripod, that is not a problem.
But when you shoot handheld—as you usually do in places like these—a shutter speed below 1/60 second produces photographs that may look fine on the camera's LCD screen but turn out extremely blurry and essentially unusable when you open them on your computer or print them.
Set the camera to f/1.8 or f/1.4 and shoot handheld, and you will get sharp, clear photographs in most settings. In this case, less—a lower number—really is more. I reach for this lens right away when... I am photographing a wedding .
A Trick for Even Sharper Photos!
Sharpshooters hold their breath when they fire. You can use the same technique when you shoot—with your camera. That's right. Many professional photographers exhale before taking a handheld photograph. Or they take a deep breath, hold it, and then take the shot. This keeps both your body and the camera as still as possible.
Read more in Scott Kelby's Digital Photography book.
