In North America, televisions and video cameras offer a variety of resolutions and two primary frame rates: 30 or 60 frames per second. In actuality, though, that 30 is really 29.97 — and 60 is really 59.94. This is not something most people care or need to know, but if you have wondered how this strange number was chosen, Matt Parker of Standup Maths has you covered with the above video explanation.
It all goes back to when color was introduced to TV. During the black-and-white era, TVs did run at a true 30 FPS. But in order to add color into the mix, frame rate had to be dropped by .03 FPS to make room for the color information in the 60Hz signal. This became the standard for all National Television System Committee (NTSC) sets in North America.
Interestingly, an alternate solution to this problem would have been a slight bump in resolution, which is what happened across the pond with Europe’s Phase Alternation Line (PAL) standard, although frame rate, at the time, was capped at 25 FPS.
The other popular frame rate is 24 FPS, which originated with cinema film production and continues to be the standard for movies even with digital cinema cameras. But in order to conform to 60Hz, the first digital video cameras that offered 24p actually shot at 23.976 FPS. This is still the standard, though many cameras now offer true 24 FPS as well.
But do you need to be concerned with any of this? Not really. To the human eye, the difference between 29.97 and 30 FPS is imperceptible, which is why we still refer to it as 30 FPS. But the other important takeaway from Parker’s video is that these numbers simply no longer matter. Modern HD broadcasts still have to conform to a standard that can scale to older televisions, but today’s sets otherwise would not have these limitations. So shoot whatever frame rate you want — or whatever your camera offers.