Essentially street photography is a form of documenting life as it happens, often in urban environments. Although difficult to precisely define, what separates street photography from other forms of documentary is a sense of reaction to life as it occurs in front of the photographer. Nick Turpin on the In Public website suggests that street photographers take shots without a concept or agenda in their minds beforehand; they snap what they see and don't set out to capture a particular theme or subject matter.
Another form of photographic documentary, typologies are collections of shots united by a theme which is immediately obvious to the viewer. For example, the photographer may present a dozen shots of elderly women wearing a duffel coat or young male skaters in street clothing or airships made from similar materials and of the same size. The idea is to offer to the viewer both interesting similarities and differences simultaneously.
In this form of film documentary, the cameraman is purely an observer to the action he is recording. He plays no part in the proceedings, and is completely neutral, simply allowing events to take place. No part of this sort of documentary is staged and those filmed may not even be aware that they are being recorded. The idea is that the film produced captures a place or subject as realistically as possible.
In these film documentaries, the filmmaker is part of the action. The level of her interaction can vary from simply interviewing or prompting the subjects of the documentaries with occasional questions, to actually playing a large role in the action, speaking to the audience directly and acknowledging the artifice in creating the documentary. In these documentaries, the creator influences and may even have a major impact on what the film captures.
These filmic documentaries are much like fly-on-the-wall features, except that they are narrated by an unseen person, who explains to the audience what is being seen and gives background to it. This verbal commentary influences how the audience sees the action and people filmed. An example of this kind of documentary would be the news reports seen on TV.