Aperture: Shallow Depth of Field

Aperture refers to the opening in the lens through which light passes before it reaches the film. The aperture can be large or small, or somewhere in between. Remember the experiment we did with the door and the window... an aperture is no different. The aperture is described by an "f/" number, such as f/4, f/11, and so forth. The "f" refers to the focal length of the lens, which we'll discuss later. All you really need to know is that the "f" stands for a number, which is divided the the number below. Thus f/4 is a larger opening than f/8 (think of a pizza, would you rather be offered 1/4 or 1/8 of a pizza? Which is larger?). The largest aperture you're likely to see is f/1.8, the small is f/32. Each drop of one number in the aperture (i.e. f/4 to f/5.6) reduces the light by half... each increase of one number in the aperture (f/16 to f/11) doubles the amount of light coming in.

When the aperture is open (such as f/2, f/4), the amount of picture that is sharp is shallow, thus the term "shallow depth of field". The giraffe picture gives you an example... the subject is sharp, but the background is blurred. Your assignment, due Oct. 3, is to turn in a print (with contact sheet and data sheet) demonstrating shallow depth of field. On this blog you should add comments about subjects you think would be suitable for shallow depth of field, along with questions. Good luck!