By using a high aperture setting such as F22, Deep Depth of Field can be achieved. This means that objects on different focal planes, or different distances from the camera lens, all appear in focus. In the image above; the face of the boy, the fence, and the kids in the yard are all in focus. On our lens, the F-stop is set by turning the aperture ring to the green line. Notice in the lens to the right that this closes the Iris down to a small opening.

Using the F 8 Aperture setting we can follow the depth of field chart on the lens to see how much of our image at a given focal point will be in focus. In this case focused to just beyond 1.9 meters, our image will remain in focus between 1.5 meters and 2.5 meters. Thus with this new setting, the same composition as before will now look different, because the boys in the far yard are beyond the focal range of this setting, thus rendering them out of focus in our new image. The fence and the boy, however, remain within the focal range of this setting thus we see them in focus.

 In this final image, shot with a low F stop such as 1, we see that not only is
the distant yard out of focus but now the fence in between is also beyond the range of focal acuity, leaving only the boys face in sharp focus. This type of image is known as: Shallow Depth of Field.





Aperture [ap•er•ture]
The word Aperture is derived from the Latin : Apertura, which can be translated roughly as opening or window. In optics, an aperture is a hole or an opening through which light travels. 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.

Common Apertures or  F-Stops:

1, 1.4, 2, 2.8, 4, 5.6, 8,

11, 16, 22, 32, 44, 64 

The camera to subject distance is fixed at the time of exposure. It usually involves a range of distances that will be in focus followed by a series of distances with decreased focus as they expand in distance, further and closer from the lens. 

Depth of Field

(D.O.F.) is determined by these four factors:

-camera to subject distance

-the lens focal length

-the f-stop

-the format size or circle of confusion criterion

Each of these factors affect the focus of an image in different ways and each is altered by changes made to the other factors.

The lens focal length is determined by the size and shape of the lens. Some lenses are created for up close photography (Macro Lenses) while others are designed for far away (Telephoto). There are narrow angle lenses and wide angle lenses, fixed lenses and zoom lenses. The focal range is notated as a single numeric value for fixed lenses(50mm) or a range between two numeric values  for zoom and compound lenses (15-200mm).