Understanding Autofocus Points

Modern DSLR cameras incorporate several focus points, which you typically can see through the viewfinder or on the LCD screen. With most older DSLR cameras, these points were visible only through the viewfinder, but as Live View mode has become popular on modern DSLR cameras, photographers can view these focus points on the LCD screen or in the viewfinder.

What Are Autofocus Points?

Autofocus points are what the camera uses to focus on a subject. You'll probably first notice them when you press the shutter halfway. Many cameras will emit a beep, and some of the AF points will light up—often in red or green—in the viewfinder or on the display screen. When your DSLR is left on automatic AF selection, you'll know where the camera is focusing by which AF points light up.

When to Use Automatic AF Selection

Automatic AF selection works well for many types of photographs—for example, if you're using a big depth of field and aren't shooting anything that's moving. But with certain subjects, the camera can get confused.

Say you're trying to shoot a butterfly on a leaf with a high-contrast background. The camera might focus on the more distinct contrast at the back, blurring the primary subject and keeping the background in focus. In such a situation, it's better to use manual AF selection.

Manual AF Selection

Manual AF selection often allows you to select only a single AF point, which gives you a precise area on which to focus. You should be able to select the exact type of AF point system that you want to use through the camera's menus. And if your DSLR camera happens to have touchscreen capabilities, you might be able to select the AF point by touching the part of the scene.

Some modern cameras, such as the Canon EOS 7D, have clever AF systems that allow you to pick single points and also a group or section of the photo on which to focus. AF systems are becoming more sophisticated, thus reducing the risk of improper focusing.

Using Many AF Points

Action shots, pets, children, and other subjects and situations with a lot of movement benefit from using many AF points. If you shoot mainly portraits or landscapes, though, you'll probably be happy with a bare minimum of AF points, given that you can adjust your subjects or your position easily.