Golden Ratio
In my photography composition lecture I teach a section on golden-ratio proportions and its relationship to the 3:2 viewfinder aspect ratio found in the 35mm camera. I also talk about how these relationships are found throughout the plant and animal kingdoms and how they were incorporated into the design of classical architecture.
In the picture at right I have overlaid a golden section spiral over one of my photographs illustrating the connection with the 35mm viewfinder. If you measure a 35mm negative you will find that it is actually 36mm x 24 mm, which is a 3:2 aspect ratio. Notice also that the golden section rectangle enclosing the golden spiral is not exactly 3:2. The important thing to understand about using the golden section ratio in composition is not to obsess about exactitude. As pleasing ratios go, our brains don't mind things being a little off--but not too far off. A German study regarding facial attractiveness seems to give credence to this assertion, at least as it pertains to perfect symmetry.
Because action and faces are both visual magnets, the focal point of the image has to be the open mouth of the rooster on the left. An open mouth that is also the nexus of three golden section rectangles makes for a very strong focal point. As I was moving my camera and framing the shot I really was not consciously visualizing this geometric overlay. When I was happy with the total composition, I released the shutter. When viewing the negative later, I instantly realized that the composition was related to the golden section. This is really not that difficult to do because you need only to visualize a square from top to bottom tangent to one side or the other; that line is roughly a golden section ratio. Also, notice that the rooster's mouth falls exactly where three major rectangles converge. This area is known as a sweet spot and is also related to the rule of thirds compositional framing method. Since a golden rectangle can be flipped and tucked in any corner of the frame, the result is that there are four sweet spots in a 35mm picture frame.