Definition: Aperture

Since I decided to put Aperture in the title of my blog, I thought it might be a good idea to really give it a solid definition.  The dictionary definition is: "In optics, an aperture is a hole or an opening through which light travels. More specifically, the aperture of an optical system is the opening that determines the cone angle of a bundle of rays that come to a focus in the image plane. ...".  In more normal terms, when you look at a lens it has a whole where light enters.  The aperture of the opening describes the width the the diameter.  When speaking about aperture, new photographers will often gets confused because the higher the F-Stop number means that the opening gets smaller.  A really good description can be found here.

An example of using a wide aperture to get a shallow depth of field.  The ladybug is in focus, flowers going out, and background is totally blurred.

I often find myself shooting in aperture mode because it allows me to easily use the auto features in the camera, with only a minimal number of options to tweak.  I am hopefully going to get a Nikon F/1.8 50mm lens soon so I can really start trying out small depth of field photos and getting shots in low light.  The aperture setting is one that is often misunderstood but once you can understand how it affects exposure, you can really use it to your advantage.