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Comment by mod50ack | Hacker News Reader

Because 60fps and 24fps don't look alike and video shot at a very high frame rate can look off to an audience.

Remember also that typically a 1/2 rule is followed where the exposure of each frame is half the time of its display. So for each of the 1/24s intervals, an exposure is made for 1/48s. A shorter exposure would have less motion blur but look jittery. A longer exposure would look too buttery. People are extremely used to 1/48s exposures displayed for 1/24s (or similar).

48fps video in the Hobbit movies was very negatively perceived. It looked too much like a video game.

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24 FPS can look "off" to an audience, too.

As someone who hates 24fps, because it looks way too jerky, and not lifelike, the sooner we lose 24FPS, the better.

You're in the minority, I think. The Hobbit was shot in 60fps and most people found it very uncomfortable to watch. It felt like you were watching a movie set rather than a movie. Suspension of disbelief is pretty important for cinema and 60fps really messes with that.

I also think most jerkiness in 23.976/24 is due to incorrect display settings leading to dropped/skipped/repeated frames. If your display can match 23.976, even panning scenes look pretty smooth. It's the jitter that messes with our brains and looks bad.

I'm also in the 24fps hater camp.

It's not jitter that bothers me, it's the stop motion effect. It's especially bad with action sequences that have a lot of closeup shots.

This is basically every movie with any sort of action in the past decade or so. If you do closeup shots in on some fast action in 24fps you don't have to worry one bit about choreography, since it'll just be a choppy blurry mess and nobody can tell what's going on anyway.

I can agree things like sports are a lot better at high frame rates. You want to see what players are doing precisely in a live setting. But people don't watch sports in movie theaters.

I'd argue stylistically the lower frame rate works a lot better on a big screen. There's also the fact that high frame rates on a big screen seem to cause some people to get motion sick.

I personally have no issue w/ action scenes which are shot at 24fps. Yeah, there is a fair amount of blur but it all seems natural (at least on a cinema projector), and conveys the fast movement, even if it might not be precise.

Take Jackie Chan's Drunken Master epic final fight scene for example - yes it's a bit blurry but I can make sense of everything going on. If anything it enhances the feeling of action - if this was shot at 60fps, it would look much more "real" and be a lot less enjoyable.

1: https://www.youtube.com/watch?v=lwDU3IOBEIk

It’s worst on panning shots where everything is noticeably jittery.

There are always a lot of unsatisfying hand-wavy answers to this question just saying that high framerate video looks "off" or "like a soap opera". I'd like to point out that the biggest factor here is probably the lighting.

Cinematographers have to pick particular aperture and ISO to get the depth of field and film grain they want, so they can only really adjust exposure though shutter speed. If you double the framerate, the minimum possible shutter speed halves. Therefore (unless you are shooting outside on a sunny day) it is very likely that your shot is underexposed, and the only thing you can do about it is add more lighting. This can be both logistically complicated and technically very hard to pull off without looking unnatural, especially in scenes that are supposed to be dark and moody.

Actors in heavy costume will get hot under that much lighting, even with LEDs. Makeup melts. Higher frame rate increases editing costs.

I wonder what the viewing experience would be like if it were shot in 48fps, but then most alternating frames were dropped so it still felt like 24fps, except for certain key visual sequences - action, big effects shots, etc. You could even transition between the two frame rates over a few seconds.

Technically one can shoot at whatever fast enough, then apply the right pulldown, exposure and blur to compensate.

Hobbit's 48 fps version was not as badly received as you make it, though the unreal slow 24 fps shoot does give it more of a fairytale character.

I am curious if the video game effect is a function of the fps or exposure time. Would a video of 48 fps with 1/48s exposure look off?

Not sure how a camera would be built that could do this...

The overlong exposure would make the video twice as bright, and if lighting is adjusted, twice as noisy instead.

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