Better Photgraphy Tip #2: Using Aperture to Control Focus

Take a look at most cameras and chances are you will notice a setting on your camera's dial either marked by an "A" or "Av." This is your camera's aperture priority setting and it can be a useful tool in taking better photos. Besides controlling the amount of light that is allowed to pass through the lens, the camera's aperture also controls the "depth of field." Defined simply, "depth of field" is the amount of "stuff" that is in focus in an image. This can be very useful when you either want to show the vastness of a scene, or you want the viewer to focus on one thing in an image. To create a photo, say for example, a landscape, that shows the vastness of a scene, you will a large depth of field. This can be achieved by setting your camera's aperture to a high
f-stop number (ie: f32, f16, f11) (Note: An f-stop is the measurement of the opening in the aperture). On the other hand, if you want a picture that is focused on one particular subject, a shallow depth of field is a good way to achieve this. To get a photo with a shallow depth of field, set your camera's aperture to a low f-stop number (ie: 2.8, 4, 5.6).

A photo with a large depth of field.

The same subject in a photo with a low depth of field.