depth of field photographyDepth of field is defined as the range in a scene, from near to far, that is in sharp focus. Depth of field provides depth, among other things, to your picture, thus giving it life, not like a flat two-dimensional photograph.

Technically, depth of field is achieved when there are subjects in various distance in relation to the lens. You then adjust the focus by manipulating the aperture. A smaller aperture creates more depth of field, a larger aperture produces the opposite effect. Depth of field is dependent on lens focal length, aperture, and distance from the subject.

With all things equal, shorter focal length lenses, smaller apertures, and greater lens-to-subject distance increase the range of sharp focus. Longer lenses, wider apertures, and a shorter distance to the subject, meanwhile, decreases depth of field.

The ability to control how much is in focus effects your shots immensely. Shooting a landscape entails as much focus as possible, so a high depth of field is needed. In the opposite end, taking a portrait requires a shallower area of sharp focus, isolating the subject from the background.

Although this is taught in basic photography, depth of field intimidates beginners because it is hard to pull off. There is a caveat with camera viewfinders. In point-and-click cameras, you are not viewing directly through the lens. Instead, you are looking through a separate viewfinder. In SLRs, on the other hand, you are looking through the lens at its widest aperture. It closes to a smaller f/stop only at the instant you press the shutter button.

SLRs have a feature called a depth of field preview button. When you press it, the lens will briefly close to the shooting aperture, showing you the real depth of field. Take note that when you press this button, the image in the viewfinder will temporarily darken. If too much is in focus, simply open the aperture, put on a longer lens, or move closer. Or do all three.