The artistic preoccupations of the new generation of documentary filmmakers don't break with those of earlier generations; rather, they have their roots in decades-old films, in which the same ideas and practices sometimes turn up in forms—embodying the filmmakers' relationship to their subjects—that seem daringly original even now. The most artistically advanced documentaries are those in which the participants are engaging conspicuously with the filmmakers; in their most radical forms, they show the influences, inspirations, or perturbations that the people onscreen experience from the filmmakers' presence. Which is another way of saying that, although documentaries follow real people, their crucial material and subject is nonetheless performance.
Throughout its history, the very idea of documentary filmmaking has shifted according to what was—and was not—possible at any given time, owing to the nature of movie equipment. Because cameras in the silent-film era were cumbersome.