Early film (pre-1900) was dominated by the novelty of showing an event. They were single-shot moments captured on film: a train entering a station, a boat docking, or factory workers leaving work. These short films were called “actuality” films; the term “documentary” was not coined until 1926. Many of the first films, such as those made by Auguste and Louis Lumière, were a minute or less in length, due to technological limitations (example on YouTube).
Films showing many people (for example, leaving a factory) were often made for commercial reasons: the people being filmed were eager to see, for payment, the film showing them. One notable film clocked in at over an hour and a half, The Corbett-Fitzsimmons Fight. Using pioneering film-looping technology, Enoch J. Rector presented the entirety of a famous 1897 prize-fight on cinema screens across the United States.
In May 1896, Bolesław Matuszewski recorded on film few surgical operations in Warsaw and Saint Petersburg hospitals. In 1898, French surgeon Eugène-Louis Doyen invited Bolesław Matuszewski and Clément Maurice and proposed them to recorded his surgical operations. They started in Paris a series of surgical films sometime before July 1898. Until 1906, the year of his last film, Doyen recorded more than 60 operations. Doyen said that his first films taught him how to correct professional errors he had been unaware of. For scientific purposes, after 1906, Doyen combined 15 of his films into three compilations, two of which survive, the six-film series Extirpation des tumeurs encapsulées (1906), and the four-film Les Opérations sur la cavité crânienne (1911). These and five other of Doyen’s films survive.