Before beginning any video shoot, it is important to understand the goals of your project in order to select the best video frame rate to film in.
What is Frame Rate?
In order to understand what a frame rate is, it is important to first understand how video is produced and displayed. Much like a flipbook you would draw as a child, videos consist of a series of images sequenced in quick succession of one another. The speed and subsequent smoothness of the video depends on the number of images displayed within a specified timeframe. This is where the term “frames per second,” often abbreviated as FPS, comes from. A frame rate is the number of frames displayed within one second.
The First Videos
The first video ever to be filmed was produced by Eadweard Muybridge in 1887. Muybridge was a photographer who was interested in the study of motion. He was given the objective of studying a horse’s gait to determine if the horse leaves at least one hoof on the ground at all times while running or if the horse has all four legs in the air at one point within its stride. To determine this, Muybridge placed a series of 24 still-frame cameras in a row along the side of a horse track. As the horse ran along the track, Muybridge was able to trigger each camera in quick succession, taking all 24 images within the matter of a second. By displaying the images, one after another, the first-ever video was produced.
William Kennedy Dickson, under the employment of Thomas Edison, is credited with inventing the first successful film camera, called the kinetograph. This camera used a roll of 35mm film that fed up to 50 feet of celluloid film horizontally through the camera at a frame rate of 40 FPS. While projection technology was still in its infancy, Edison developed a machine in which the audience would look through a peephole as the film, produced by the kinetograph, was successively fed through and backlit by the machine. This complementary machine was called the kinetoscope, and it allowed viewers to see successive images in a continuous smooth motion for the first time in history.
At the turn of the 20th century, film technology began to rapidly advance. Film cameras became smaller, more portable, and more accessible. Projection devices had been developed, and theaters began opening across the world, allowing audiences to enjoy a film together. With the boom in popularity in the early 1900s, many different recording and projection devices became available. In order to ensure compatibility across the majority of cameras and projectors, a film frame rate had to be standardized to ensure smooth capture and playback of the captured video.
Film cameras, such as those used to produce movies, utilized a 24 FPS frame rate, matching up with most common film projectors. To this day, movies are still filmed and displayed at a 24 FPS frame rate in theaters. When film is digitized for broadcast on television or any digital display, the film is slowed down from 24 FPS to 23.976 FPS to conform with North America’s television broadcast standard called NTSC. The majority of movies continue to be shot and displayed at a 24 FPS frame rate since it is thought to offer a more cinematic experience for the viewer. 24 FPS footage is also useful in film production because it offers fewer frames per second than other standard frame rates, which allows for easier and more cost-efficient video effects, as there are fewer still images to manipulate in order to achieve the desired effect and it is easier to hide any post-production graphic effects if there are fewer frames displayed per second.
As video technology became digitized, film was no longer needed to capture motion or project an image. Digital video capture allows camera producers more freedom to create cameras that utilize a different frame rate than traditional film cameras, as matching the frame rate to the projector’s display rate was no longer a concern. For television, many broadcasts are now filmed and displayed in what is called 30 FPS or 29.97 FPS. 29.97 FPS is another NTSC standard frame rate, used in television broadcasts in North America. 29.97 FPS footage is commonly called 30 FPS, but most cameras actually record in the NTSC standard frame rate of 29.97. This is a great frame rate for broadcasts such as television shows, news broadcasts, and live sports. It offers a smooth enough frame rate that all action is displayed clearly without any noticeable stuttering.
As digital video technology has progressed, camera producers have created cameras that can capture motion at a higher frame rate. Another common frame rate increasingly used today, especially when capturing sports imagery and other motion-oriented events, is 60 FPS. The NTSC standard for this frame rate is 59.94 FPS and is, therefore, the most common frame rate used when talking about 60 FPS video. 60 FPS video is useful when filming high-speed sports, such as skiing or automobile racing, as it offers a smooth display of motion, with twice as many frames per second as 30 FPS video. Since 30 FPS is more than adequate to display a smooth video experience, 60 FPS video can be slowed down to half speed and still retain a smooth video output at 30 FPS. Today, most streaming websites, such as YouTube, offer video playback with a frame rate of up to 60 FPS.
As digital technology continues to progress at a rapid pace, frame rates have also increased accordingly. Often a higher frame rate is achieved by lowering the digital resolution a video is filmed in, as filming a higher frame rate requires more data per second to capture the increased frames. Thus, using a lower resolution allows the camera to record a similar amount of information at a higher frame rate. For example, a video camera may be able to shoot 30 FPS footage at a 4k resolution but may only be able to film 60 FPS footage at a maximum 2.7k resolution.
Frame rates of 120 FPS, 240 FPS, and even frame rates over 1,000 FPS have been achieved by recent digital cameras. These frame rates are useful for slow-motion videography seen in action sports or even research studies. Much like Muybridge set out to determine the true nature of a horse’s gait, contemporary researchers have used slow-motion video cameras to study physical interactions of objects at extremely slow playback speeds. By filming a video at a frame rate of 1,000 FPS, you are then able to slow a second of video footage down, so it takes over 33 seconds to playback and still achieves a smooth playback speed of 30 FPS.
Which Frame Rate is Best for You?
Now that you understand the differences in frame rate, it is time to determine what frame rate you will use for your own video.
- Are you going for a cinematic, film-like viewing experience? Then film your video in 24 FPS or the NTSC standard of 23.976.
- Is your video going to be played back on the internet and television? Then a frame rate of 30 FPS or the NTSC standard of 29.97 FPS is suitable.
- Does your video content involve a high amount of motion, or do you plan on slowing any of the footage down to a minimum playback speed of 50%? Then 60 FPS or the NTSC standard 59.94 FPS is the correct choice for your project.
- If your goal is to achieve an extremely smooth or slow playback of the footage that you plan to shoot, then a frame rate of 120 FPS or higher is going to be useful in achieving this goal.
By filming in the correct frame rate for the desired playback application, you can avoid the unnecessary headache of converting your footage to a different frame rate, which can potentially affect the end result of your project. For example, if you shoot a video at 30 FPS, but plan on slowing the footage down by 50%, your footage will only be playing back at 15 FPS and will look choppy. Another benefit of choosing the correct frame rate for the desired application is that of data size. As you increase the frame rate, the amount of captured data also increases. By shooting at as low of a frame rate as needed, you save data capacity and make the post-production process easier.
By following these guidelines, you will ensure that your video project is filmed and displayed in the most effective frame rate for your application.