A feature-length film is one that is the prominent, full-length movie as compared to very early films that were less than forty minutes, with several potentially being bundled together. SAG defines one as being at least eighty-minutes or longer. If you have ever seen Singin’ in the Rain (which is a classic), it takes place in the time period of the transition from short films to feature-length films and from silent to talking. They make a big deal about whether an audience would want to sit for a whole, feature-length film.
It turns out that the first feature-length film was, arguably, as early as the end of the 1800’s (which would have had to be silent; the first talking film was “The Jazz Singer”, in 1927). That amazed me. I had no idea we produced movies, of any kind, so far back.
The majority of feature films are between 70 and 210 minutes long. The Story of the Kelly Gang (1906, Australia) was the first dramatic feature film released (running at approximately 60 minutes). An earlier The Corbett-Fitzsimmons Fight (1897, U.S.) is considered by some as the first documentary feature film (running time is 100 minutes), however it is more accurately characterized as a sports program as it included the full unedited boxing match. The first feature-length adaptation was Les Misérables (1909, U.S.). Other early feature films include The Inferno (L’Inferno) (1911), Quo Vadis? (1913), Oliver Twist (1912), Richard III (1912), From the Manger to the Cross (1912), and Cleopatra (1912).
Worth mentioning is the volume of movies being produced every year between now and then. The US market produced more movies per year in the 1920’s than at any other time in cinematic history:
By 1915 over 600 features were produced annually in the United States. The most prolific year of U.S. feature production was 1921, with 682 releases; the lowest number of releases was in 1963, with 213. Between 1922 and 1970, the U.S. and Japan alternated as leaders in the quantity of feature film production. Since 1971, the country with the highest feature output has been India, which produces a thousand films in more than twelve Indian languages each year.
That is amazing considering the generally higher-quality of writing and acting then as compared with now.