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Comment by relix | Hacker News Reader

That is because a game's frame is rendered at one absolute time point, while a movie's frame is like a photograph taken with a shutter speed of 1/24th: it includes the motion data of that whole time interval, it contains motion blur, and it's smooth from one frame to the next.

That's why a game at 24fps looks bad, but an (action) movie at 24fps looks good.

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> That's why a game at 24fps looks bad, but an (action) movie at 24fps looks good.

"Looks good"? Maybe passable. And that's only because of a century of experimentation with camera techniques allowing to eschew the limitations of the format.

E.g. try giving an amateur a 24 fps camera and ask them to shoot a sequence that involves a lot of panning. The result is going to look like junk.

Even in the hands of a professional it still doesn't look good. But we've all trained our brains to shut up and accept it, because we've all watched so much 24 fps content. It's 100% pavlovian conditioning, nothing else.

To someone coming from a universe where all motion pictures are shot at 60 fps or above, our movies would look excruciatingly bad.

That doesn't seem like it could be true. The film is rolling through the camera, and if the shutter were open continuously, the entire film would be a vertical blur of light. The shutter would open and close once per frame, so the film can be advanced. The actual shutter speed of a camera shooting 24 fps would be much faster than 1/24 s.

Correct. There's a simple formula for that: http://en.wikipedia.org/wiki/Shutter_speed#Cinematographic_s...

Oh, cool. The linked article about the rotary shutter also has a great animation showing how the camera works:

http://en.wikipedia.org/wiki/Rotary_disc_shutter

You're right about the continuous roll. Film actually moves through the gate incrementally. There's a really neat mechanism that closes the shutter and advances the film to the next frame in one elegant move. But while the film is exposed, it's exposed for a fraction of a second. Meaning that any motion occurring within that second will register with a blur in that particular frame.

Just hit pause on practically any movie when there is movement

It is really interesting how our brain compensates for the motion blur in films. I mean, you don't usually notice that things are really blurry until you pause the movie.

Our brain compensates for motion blur, period, because everything we see is effectively slightly blurred due to our eyes' response to light changes being non-instantaneous.

Specifically, cone response time seems to be on the order of 15-20ms if I read http://www.ncbi.nlm.nih.gov/pubmed/14990682 correctly. And that's just to go from initial stimulation to peak response; presumably the response also dies off in nonzero time, so the full width of the response in time is more than 20ms. Rods respond slower than cones according to http://en.wikipedia.org/wiki/Photoreceptor_cell though I can't find numbers.

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