Beauty has a lot to do with math, and physical attraction depends on a ratio; a golden ratio. Everything in nature has this ratio in one form of the other. When we talk about the aesthetic of beauty we are referring to symmetry, proportion, and a recognizable pattern or method to the arrangement of the element.
Composition refers to the arrangement of the element that makes up an image. If a composition is aesthetically appealing it is because those elements have been arranged in some sort of detectable method. If the elements of an image are thrown together at random without any sort of method, it is not a composition it is chaos. It won’t be pleasing to look at and we would not recognize any pattern.
However, if those same elements are arranged with some sort of method we end up with a composition that is aesthetic. You can use contrasting colors or sizes of the element to draw attention to certain parts of the image, but there has to be a sort of method to the arrangement.
Composition in film, similarly, talks about the visual aesthetic of a shot; the lightning, the color, everything within a frame you see. It’s all about arranging the elements within a scene to guide the eye or draw attention to certain things. It’s about intent and method.
The Rule of Thirds is one method of arranging the elements within the composition. If you divide a frame with two vertical lines and two horizontal lines what you are left with is nine boxes. The idea is if you align your subject or point of interest along the two vertical lines or where the lines intercept you will end up with a more pleasing or balanced composition.
When setting up a shot or composition using the rule of thirds the most common question you should ask is; what is the main point of interest and where am I putting it? Putting an image in the dead center of a frame makes it feel flat and dull, but if it was moved to one of the vertical thirds, then a big improvement is created. Our eyes will still be drawn to the image despite not being at the center of the frame. You can also put your point of interest along the incepting line.
This method is also applicable in a landscape shot. If the horizon is filmed dead center of the frame it feels flat. But if it was moved to the upper or lower third we end up with a more powerful image. If there are two subjects you can frame them such each falls on the two vertical thirds. If you have two subjects that are very close to one another, you can treat them as one and place them at one of the intercepting thirds or along with one of the vertical thirds.
The Rule of Thirds can be applied to anything, even shadows. In a lot of movies, the visual interest is easy to follow because most of the time the subject falls on one of the vertical thirds and the background falls on top of the upper or lower third.
In the practice of the law, you can be slightly off and still create a powerful shot.