Understanding Aperture

Aperture is a measure of how much light is let through your lens and into your camera (to expose the CCD or film). The measure is called f-stops. A good regular lens will have somewhere from around f/2 to f/22. The actual aperture is either automatically controlled by the camera, and calculated due to the amount of light, or controlled by turning the front of the lens. Rather than moving smoothly, like a focus knob, it moves steadily and clicks through all the f-stops. Generally the details recorded with a picture are the Aperture, Shutter Speed, camera, film and photographer.

Click this to see what the different f-stops look like:

So now you know what aperture is and looks like, you want to know what it is for and how you can use it. Aperture, combined with shutter speed controls the depth of field. Reducing aperture size increases depth of field. Depth of field basically means how much of the image is sharp (in focus) and how much of it is blurry (out of focus). A good photographer always uses depth of field to their advantage. Generally a landscape picture has a large depth of field to make sure the whole image is sharp and a macro or close up picture is taken with a small depth of field so that the focus is only on the central point.

Here are some examples:

The Castlepoint Lighthouse, f/16, 1/30, Pentax K1000, Joe Bloggs

Praying Mantis, f/4, 1/250, Pentax K1000, John Doe