Why are Movies Recorded in 24 fps?
The answer to this question is rooted in the history of cinema, cinematography, and human visual perception. In this article, we will explore the reasons behind the widespread adoption of 24 frames per second (fps) as the standard frame rate for filmmaking.
The Golden Ratio
One of the key factors influencing the choice of 24 fps is the golden ratio, a mathematical constant approximately equal to 1.61803398875. This ratio has been observed and employed in various aspects of art, architecture, and design for centuries. In cinematography, the golden ratio is used to compose visually appealing shots, ensuring that the audience’s attention is drawn to the main subject of the scene.
Motion Blur
Another crucial factor is motion blur, which occurs when a subject is moving rapidly across the frame. When captured at a higher frame rate, motion blur can be reduced, but at the cost of increased file size and reduced dynamic range. 24 fps, however, strikes a balance between motion blur and other cinematographic considerations.
Influence of the Eye and Brain
The human eye and brain have a natural tendency to process and perceive motion in a specific way. When shown a sequence of images at a higher frame rate, the brain may have trouble distinguishing individual frames, leading to an artificial and unappealing effect. In contrast, 24 fps allows for a more natural and fluid depiction of motion.
Film and Video
The terms "film" and "video" often elicit different connotations in terms of quality, aesthetic, and even format. Film is generally perceived as having a more cinematic look, thanks in part to the traditional use of 24 fps. This perceived value of film is rooted in the technical differences between film and video. Video, on the other hand, has a more digital and, therefore, unnatural feel.
Why 30 fps is Not Suitable
30 fps, often used in video and TV production, may seem like an improvement over 24 fps in terms of motion clarity. However, the difference is marginal, and the higher frame rate comes at the cost of reduced dynamic range and increased file size.
The Standard Frame Rate for Cinema
In 1920s Hollywood, the dominant frame rate for cinema was 18 fps, due in part to the limitations of film processing and camera technology. The introduction of the Xenon lamp and 35mm film stock in the 1930s led to a shift to 24 fps, which has remained the standard for cinematic production to this day.
Comparison with 48 fps
The 2011 re-release of "The Wizard of Oz" in 48 fps garnered attention for its unique visual effect. While 48 fps has been shown to improve motion clarity, it is still not widely adopted due to the artificial feel it can create, as well as the potential increase in file size and complexity in post-production.
Conclusion
The use of 24 fps in movie production is rooted in a combination of historical, technical, and aesthetic factors. The golden ratio, motion blur, and human visual perception all play a role in the decision-making process. While 30 fps and 48 fps have their own advantages, 24 fps remains the industry standard for cinematic production, ensuring a unique and captivating visual experience for audiences worldwide.