Digital Photography

The aperture in your camera allows you to choose the depth of field (DOF) you camera will focus on. The F/stop number corresponds to how open your aperture is. A very large aperture will give you a shallow DOF while a more closed aperture will give you a very deep DOF.

Portraits are often taken using a very shallow DOF which means an open aperture. This will keep only the main subject in focus and blur the background. This can be very useful when the background can distract from your main subject. On the other hand if you are taking a scenic photograph you may want a very deep DOF so the tree in front of you is in focus as well as the mountains far behind it.