Cinéma vérité
Documentary that admits the camera is there, and treats what filming does to people as part of the truth.
Jean Rouch and Edgar Morin shot Chronicle of a Summer in Paris in 1960 and released it in 1961. Morin had used the phrase in a 1960 article, after Dziga Vertov's Kino-Pravda newsreels. Rouch and Morin accepted that filming changes how people behave, and made that change part of the subject.
Filmmakers elsewhere took up the style and tested it. William Greaves shot Symbiopsychotaxiplasm: Take One in 1968 in the manner of a vérité documentary, then let its crews turn their cameras on the production.
Films to start with
In the order they were made. Runtimes are approximate.