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What is Frame Rate for Video: Understanding Frames per Second

What is Frame Rate for Video: Understanding Frames per Second

So what is the frame rate in the video, and why are there so many options? why there are so many, and how these different frame rates are gonna affect the way your video looks.

So first off, when we're watching a film, we're not actually watching true motion. What we're seeing is a series of still images that are called frames. Now the human eye can register about 10 to 12 frames per second as individual images, but once you start getting above those 12 frames per second, your mind starts to fill in the gaps and then perceives it as being true motion.

What is Frame Rate for Video – Understanding Frames per Second & the History of Frame Rates

History of Frame Rates

Where these various frame rates came from.

So starting off with the silent film era, cameras and projectors had to be hand-cranked to advance the film through them, and this led to varying frame rates between 14 to 26 frames per second, which was enough to give that sense of motion, however it was often jerky and uneven because the film had to be hand-cranked during the recording process, and then cranked again by hand during the projection.

And these variations in speed during the recording and the playback made it nearly impossible to get a consistent true-to-life feel of motion in the films, but things began to change in the late 20s when it became possible to sync sound using various sounds recording devices with a projector.

The film could now be cranked mechanically during the recording and playback process giving a consistent speed, and eventually sound was able to be synced to the film by adding an optical track to the film strip alongside the image.

And it was this practice of linking the audio to the film strip that limited the frame rate to the limitations of the audio technology of the time.

What is Frame Rate for Video: Understanding Frames per Second

Since the film was expensive, it was important for production companies to use as little film as possible to keep costs down, and although 16 frames per second was enough to give motion and was used during the silent era, it wasn't enough to produce a quality soundtrack at that frame rate.

So eventually the production companies settled on 24 frames per second because it was the slowest frame rate they could use that gave good audio quality. So the 24 frames per second that we're used to seeing in films wasn't a decision based on the way it looked, but more of an economical decision to keep costs down. So my camera has 24 frames per second, but I also see 25 frames per second and 30 frames per second.

Where did these come from?

For about 50 years TVs were made using CRT monitors (cathode ray tube) and the limitations of the vacuum tube technology at the time required that the displays be refreshed at an AC line frequency. Now that's the flow of electric power running through the lines in your walls, and this has an AC line frequency of 60 Hertz in the US and 50 Hertz in Europe.

What is Frame Rate for Video: Understanding Frames per Second

And that AC line frequency limited TV refresh rates to a multiple of 60 in the US and 50 in Europe.

So now 24 frames per second, which is what was used for film at the time, was no longer applicable for television because it wasn't a multiple of one of those AC line frequencies.

  • So the U.S. adopted the NTSC format (National Television System Committee) which is 30 frames per second.
  • And Europe adopted the PAL format (Phase Alternating Line) which is 25 frames per second.

So because of technology limitations, 30 frames per second has been the standard for broadcast production, whereas 24 frames per second has been the standard for film production. However, now cameras, projectors, and televisions all support varying frame rates and formats leaving filmmakers and videographers able to break free from the limitations that technology had previously on them and shoot in whatever frame rate is appropriate for their audience and their content.

What frame rate are movies shot on now?

24 frames per second is still the standard because that's what we've been conditioned to see and film for over half a century, however, there has been a move towards using higher frame rates in film. Like in "The Hobbit," where director Peter Jackson filmed it at 48 frames per second because he argued that it made a clearer film, especially for 3D. If the camera is capturing twice as many frames per second, it removes motion blur and gives a much clearer picture of what's happening.

Now, research has suggested that our brains perceive the world at 40 conscious moments, or frames per second. So the problem for some with The Hobbit was that it was providing almost too much reality for a film at 48 frames per second when moviegoers have been so conditioned to seeing the film at 24 frames per second. So for some people, because these higher frame rates are so much different from what they've been conditioned to see in film for decades, they reject it.

  • Using higher frame rates can also cause issues when it comes to post-production work.
  • Using higher frame rates will increase the cost of color grading, motion graphics, keyframing, CGI, and other post-production manipulation of your footage because there're more frames that have to be manipulated.
  • And more frames per second also require greater processing power, more storage, and labor costs.

Simply put, higher frame rates cost more money so there will always be an economic benefit to using fewer frames per second. But the great thing is now you have the option of so many different frame rates without the limitations that were previously there.

So whether it's a high or low frame rate, use what's best for your project based on your budget, your audience, and your method of distribution. Even though we've been conditioned to a certain frame rate for so many years, you can always experiment and see how you like different frame rates, see what works for your projects, and make your own style. let me know down below about what your favorite frame rate is.

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