The Playhouse
Directed By: Buster Keaton and Edward F. Cline
Released: 1921
Length: 22 min
From the Wikipedia article:
The film is set up as a series of humorous tricks on the audience, with constant doubling, and in which things are rarely what they at first seem to be.
It opens with Keaton attending a variety show. In this first sequence, Keaton plays the conductor of the orchestra, every member of the orchestra, the actors, the dancers, the stagehands, the minstrels, and every member of the audience, male and female.
This elaborate trick-photography sequence turns out to be a dream when Joe Roberts rouses Keaton from bed. The bedroom then turns out to be not a bedroom, but a set on a stage.
Keaton's portrayal of nine members of a minstrel show required the use of a special camera shutter. It had nine exactingly-machined strips of metal which could be moved up and down independently of each other. Elgin Lessley, Keaton's cameraman, shot the far-left Keaton with the first shutter up, and the others down. He then rewound the film, opened the second segment, and re-filmed the next Keaton in sequence. This continued for each of the remaining seven Keatons.
The camera was hand-wound, so the Lessley's hand had to be absolutely steady, with no variation in its speed. Keaton had to move meticulously in each of his appearances, so he relied on a metronome to guide him, not a problem in a silent film.
