There are no rules, not.

When I joined the RA Photo Club a few years ago I thought I had a pretty good handle on what made a good photograph. I had read a few Freeman Patterson books, and thought I understood light. Wrong.

After a few competitions at the Club with judges comments, a few visits to the critique sessions, and a few presentations by photographers at the Club, I realized there are a lot of rules. The rules are softened by comments that they are made to be broken, but like the Duck says, good art as a lot of rules.