It is all about my never ending quest of looking for the perfect composition and aspiring to make better photographs. Phi is the golden section, the golden ratio and the golden rectangle. The divine proportion, which is perfect and harmonious, 1.618.
According to Wikipedia, "Phi is used as a symbol for the golden ratio. This use is separately encoded as the Unicode glyph ϕ. Some twentieth-century artists and architects, including Le Corbusier and Dalí, have proportioned their works to approximate the golden ratio - especially in the form of the golden rectangle, in which the ratio of the longer side to the shorter is the golden ratio - believing this proportion to be aesthetically pleasing".
What does this have to do with photography, you might ask? A full frame 35mm camera has an aspect ratio of 3:2, which happens to be very close to the proportions of the Golden Rectangle (3.2:2).
We only need to consider one of the greatest photographers of all time to see how this affected his work. Why was Henri Cartier-Bresson so exceptional? It is because the foundations and composition of his photographs are so perfect. It is all about composition and geometry. What is inside the frame, what is excluded and how he arranges all of the elements. He started out and trained as a painter under the tuition of André Lhote, the Cubist painter, who instilled in him an obsession with composition. Cartier-Bresson would acknowledge that Lhote had “taught me to read and write. That is to say to take photographs.”
“You need to connect both the emotion of a subject, and the joy of artistical organization. The intuition of the golden number, a rigour of balancing the shapes. Well, those are the basics for me.” H.C.-B.
"If you start cutting or cropping a good photograph, it means death to the geometrically correct interplay of proportions." H.C.-B.
“In order to ‘give a meaning' to the world, one has to feel oneself involved in what he frames through the viewfinder. This attitude requires concentration, a discipline of mind, sensitivity and a sense of geometry.” H.C.-B.
My greatest influence and inspiration will always be Mr. Cartier-Bresson.