The rule of thirds is used by visual artists of all kinds. The idea is basically this: when you compose a scene (whether it’s on canvas or in your camera’s viewfinder), you can make the scene stronger by positioning the most important elements at the intersections of imaginary lines that break the frame up into thirds (two horizontal and two vertical lines that form a nine part grid). Of course there are arguments as to *why* we do this–some say it creates energy and tension while others say it creates a feeling of balance in the photo. Personally I agree with the latter, but you be the judge.
The photographs below demonstrate this rule. Notice that the first image goes beyond simply placing the important part (the subjects’ heads) at the intersecting lines but strengthens the photo by having the edge of the bench fall along the bottom line. This is similar to placing a landscape scene with the horizon at one of the horizontal lines as opposed to directly in the middle.
Now look at this image, in which I’ve placed the subject directly in the middle of the frame. Does this image *feel* different than the images above?
Like all rules, they were made to be broken. So don’t feel that you MUST follow it from now on. As you can see in the photo above, sometimes the strongest images DO break the rules. But you can’t break the rules if you don’t know them…