pictures meant only the movement that is perceived when a string
of celluloid - recorded images are projected at a rate of 16 or more
frames per second (see persistence of vision). Today, motion pictures
(or "movies") are an art form, as well as one of the most
popular forms of entertainment.
A feature film is usually defined as being more than 60 minutes
picture film was shot at a nominal 16 frames per second, but was
changed to 24 frames per second with the introduction of sound.
Other improvements since the late 1800s include the mechanization
of cameras, allowing them to record at a consistent speed, the invention
of more sophisticated film stocks, allowing directors to film in
increasingly dim conditions, and the development of synch sound
- , allowing sound to be recorded at the same speed as its corresponding
video. Since the advent of many other media technologies, film may
include a broad range of media - - both linear and non - linear,
dramatic and informational, motion and still (though progressive).