Portrait types
Snapshot: Informal photograph. It is not a true portrait, because it does not reveal much about the subject.
Environmental: The background is not out-of-focus, it is a part of the picture. it does not have to be an outdoor picture. Elements in the background should help tell the story. Unlike a snapshot, it should tell something about the person. A popular technique in pet photography.
Candid: Subject unaware (or posed in a way that gives that impression). The idea is to capture a moment. Typical paparazzi shots.
Formal: Every aspect of the photo is planned out ahead of time. Generally the goal is to make a flattering image. The better ones also reveal something about the person.
Commercial: More edgy than formal, with artistic flair.
