Understanding Shutter Speed

Shutter speed is the amount of time which the shutter is open to allow the film/sensor to be exposed to light. This speed is generally measured in fractions of a second such as 1/250. The faster the shutter opens and closes, the less light strikes the film or digital sensor.

The Aperture

Aperture describes the size of an opening within the camera lens that allows light to pass through the lens. The aperture works with the shutter speed to control the amount of light striking the film or digital sensor. Aperture is generally measured by F-Stop. Aperture also has a secondary effect of controlling the depth of field of an image.

How Depth Of  Field Works

The depth of field describes how much of an image is in focus from front to back. Dept h of field is controlled by the aperture as well as the lens magnification. Some images, such as portraits, have traditionally used mostly small depth of field in order to blur the background. Other images, such as landscapes, traditionally use much larger depth of field in order for the entire vista to be in focus.