A Little Great: A Little Photography...Aperture

If you can master aperture you gain real creative control over your camera. In my opinion – aperture is where a lot of the magic happens in photography and as we’ll see below, changes in it can mean the difference between one dimensional and multi dimensional shots.

Aperture is the size of the opening in the lens when a picture is taken. Aperture is a function of the lens. Lenses contain a diaphragm, a thin light-blocking plate or interlocking set of adjustable plates. The diaphragm contains a small hole, called the aperture. This hole is adjustable in size and allows the photographer to determine and control the amount of light entering the camera. Below is an image of a 50mm lens with the diaphragm or aperture wide open and the aperture closed tight.

One thing that causes a lot of new photographers confusion is that large apertures (lots of light gets through) have smaller f-stop numbers. Smaller apertures (less light gets through) have larger f-stop numbers. So f/2.8 is in fact a much larger aperture than f/22. It seems the wrong way around when you first hear it but you’ll get the hang of it. Here's a diagram to help...

Lower f-stops (wider aperture) give a shallow depth of field (DOF). This allows you to isolate the subject from the background. Shallow focus typically is used to emphasize one part of the image over the other.

Here are some examples...

Shot at 2.8f

Shot at 1.8f

Shot at 2.8f

Higher f-stops (narrow aperture) gives a deep DOF. In deep focus the foreground, middle-ground, and background are all in focus. Deep focus requires more light to achieve than shallow focus because the aperture is narrower letting in a smaller amount of light.

Here are some examples...