The intention is that the picture stays clearer on digital displays when objects move quickly.

FYI there are monitors now advertising 360hz refresh rates.

So 24 fps is NOT the limit the typical human eye can detect motion. It was a standard made in the 30's or so in order to get AUDIO working consistently on film. We've stuck with it since then in part because physical infrastructure was built around that - projectors, splicers, etc. but also because the typical audience has grown accustomed to the look, and anything else feels 'wrong' when watching a movie.

With digital, physical limitations are not a concern, so you see games pushing refresh rates faster and faster, and even some films are entering that territory. Going with a faster refresh rate means you have less motion blur on each frame, giving you more clarity in frame. This seems great IN THEORY, but as the Hobbit proved, you also have to make your production design much more sophisticated if you can't rely on motion blur to hide the finer details - otherwise you end up with that sopa opera look.

60 fps is about the refresh rate where you get a similar amount of blur that your eye naturally perceives through its photo-chemical processes per frame. There's an anecdote of a projector manufacturer trying to impress Steven Spielberg by showing off a higher refresh rate theatre. He had Spielberg sit in the middle of the theatre, but then came on stage up front to let him know there was a technical error, and Spielberg responded it was fine and he could wait. But that was actually a feign - the man on the stage was a projection filmed at 60hz and Speilberg's eyes fooled him into thinking the man was real.

As for why 60 is the standard (vs 48 or 72) its mostly because 24fps (or 23.976 to be exact) is actually the odd-one-out when it comes to standards. NTSC's standard is 30 and since its the game industry that has been driving the increase in framerates, they also went along with what monitors could do. The gold standard would be 120fps because thats a multiple of both 24 and 30. You can record that image/data once, and then output to either format without frame blending interpolation. (Though you would need to add motion blur in post to the 24fps version, or it would appear strangely crisp, like a stop motion film from 30's-90's.) Motion blur is also expensive to compute in games, and prone to errors. By pushing the frame rate into the 90+ range, the human eye can provide the blur naturally, and that doesnt need to be included in a render pass.

In terms of what the eye can actually perceive, this number is somewhat debated. It's a SKILL that can be honed like any other muscle, and different depending on your physical and mental circumstances. You may subconsciously notice a higher frame rate, but your brain may not consciously pick up the difference. I've been an animator for 18 years and I can certainly tell the difference between 60 and 90 hz because I've had to analyze footage at those speeds for my job for years. With 90-120hz is more difficult to discern a difference for me, but I'd be willing to bet that some gamers have developed a better subconscious feel for that with practice, time and good hardware

Thanks a ton for the answer, Kensington!

Given how year has been going, I vote we just scrap all entertainment until 2022, catch up on the classics, and come back with a roar in a new format.

120 FPS sounds pretty logical, but if we just multiply 24 and 30, we get a nice round 720.

You're watching CrabTV! 720 fps, 720 resolution.

It's useful when you have to track fast moving objects and breaking immersion by looking like a soap opera doesn't matter.

It's why it only doesn't look like ass for sports (fast moving, immersion isn't the point) and video games (fast moving, not photo realistic enough to make you think it's real).

A couple of Ang Lee films were shot and released in 120 fps but it didn't go down well. I think it would be cool for documentaries.

IIRC, the max detectable by human eye is 60.

Fun fact: your eye doesn't work on frames! You're not a computer!

And yet, the person who gave the actual answer knew exactly what I meant, down to the number I mentioned.

Also, if I'm not a computer, how come all my friends say I'm plug n' play? Explain THAT, Mr. Jobs!

My life changed when I went from a 60hz monitor to a 144hz monitor.

I went from a 60hz monitor to a 120hz TV and...I cant tell if the difference in quality is because of refresh rate or going from cheap LCD to premium OLED.

Guessing for this to work well it will have to be drawn intentionally with frame interpolation in mind, instead of the least amount of frames possible and all sorts of distorted drawing tricks to fool the viewers’ eyes.