DAY 131

PHOTOGRAPHY 101

Focus and Depth of Field

MAPPING WITH CLARITY

Earlier articles reviewed the depth of field as it relates to your aperture setting and the art of focusing; now we’ll cover the finer points of focusing as it relates to the depth of field.

When you focus on a subject, that subject is in the “plane of critical focus.” It is a very tight area that is in perfect focus.

There is also an area in front and behind the area in focus that are in reasonable focus. This is the area that is referred to as the depth of field. The further an object is away from the plane of critical focus, the more out-of-focus it will appear.

Most often, the areas to the front and the back are not equal. Generally, the area of reasonable focus is about one-third in front of the subject and two-thirds behind, except when you are focusing very close to a subject, perhaps with a macro lens. In this case, the areas in reasonable focus in front of and behind the subject are about evenly divided.

Depth of field can also be different for different focal length lenses. The shorter and wider the lens (or the lower the number of its focal length), the greater depth of field available.

The distance you are from your subject also affects depth of field. The further away you are, the more depth of field is available to you than if you were using the same lens at a closer distance. —CWN