Photography - Aperture

The aperture is a small set of blades in the lens that controls how much light will enter the camera.  The blades create a octagonal shape that can be widened or closed down to a small hole.  Shooting with the aperture wide open, then more light is allowed into the camera than if the aperture is closed down to only allow a tiny hole of light to enter the camera.Simply speaking, if the picture is too bright,  to fix it is simply choosing a smaller aperture. Aperture sizes are measured by f-stops.  A high f-stop like f-22 means that the aperture hole is quite small, and a low f-stop like f/3.5 means that the aperture is wide open.

The aperture also controls the depth-of-field. Depth-of-field is how much of the picture is sharp, and how much is blurry.  If you want to take a picture of a person and have the background be blurry, you’d use shallow depth of field.  If you want to take a picture of a mountain, you’d want to use a small aperture size (high f-stop number) so that the entire scene is in sharp focus.