What you say Casey is what Susan Sontag sort of implied: a photographer becomes known when he adheres to a type of photography. But I don't agree much with that. There are several things that are explored by a photographer: context, as Echi says, subject matter, and "style". They don't necessarily interact. One can be a photographer for example of light, which is not a subject matter. Context can have several meanings. But there's that something always that you recognize as a good photograph and it's difficult to explain.