What is frame rate?
Also known as frame frequency, the frame rate is the frequency at which consecutive images called frames, are displayed per second. This is usually represented in hertz (Hz). This applies both in the case of films, video cameras, and computer graphics. On average, a human eye will consider anything that is above 20 frames per second as a moving image.
Silent era and frame rate
During the 1880s when videos had just been introduced, the frame rate was from 16 to 24 fps (frames per second), but Edison suggested that anything that is less than 46 fps can cause strain to the eye. In the 1920s, the frame rate was increased to between 20 and 26 fps by the Lumiere brothers.
Sound films and frame rate
When sound was introduced in the industry, people were more sensitized towards audio frequency and variations in film speed were no longer tolerated. Therefore, 24 fps was made a standard for a 35mm sound film.