Hacker News Reader

Comment by rkagerer | Hacker News Reader

So I thought humans aren't supposed to be able to distinguish above ~30 fps. I've always been a little skeptical of that because faster framerates seem subjectively smoother to me, but I was willing to write that off to psychological bias or sync/timing artifacts between interfaces or whatever.

Maybe someone out there can clear this up for me and convince me why we need 120+ fps displays?

EDIT: Well, nevermind, a quick google search corrected my misconception about 30fps.

View on HN

I always remembered the original saying is that human will consider things "animated" when it's above threshold (24fps or whatever).

Telling 24, 30, 60 apart is very trivial.

As for 120fps, you need to keep in mind that playing a real-time rendered computer game is a totally different beast than playing back a steady video. There are lots of other factors involved. Some headroom in FPS makes lots of difference due to various other things like jittering (judder?), input delays, response time etc. (also it's possible some people simply can tell 60/120 apart, even by just watching a video.)

Another big difference is that motion in video frames are smeared because of a (simulated) shutter speed. Whereas a video game every frame is perfectly crisp. This makes a huge difference on the smoothness experience.

60hz vs 120hz is also obviously apparent if you have them next to eachother (when using multiple monitors, for example). Just jiggling the cursor around or scrolling a webpage makes the 60hz look almost stuttery in comparison. Same goes for UI stuff like the animated dropdown of a menu.

Same experience for me. The 30hz, 60hz, 120hz are indistinguishable thing is a console gamer lie

My naive understanding is that some of it is because if you follow an object on the screen with your eyes, it gets motion blurred on your retina as it stays still for ~1/30 s on the screen while your eyeball moves.

It is possible to improve on this without increasing the framerate with strobing the backlight/black frame insertion.

For most realtime 3d animation, I wonder whether it's that the camera effectively has an infinite shutter speed, so you lose the natural motion blur you get when real film and our retinas get exposed to short durations of changing light. That changing light and blur carries information that is not rendered by most games. Quadrupling the frame rate will add some of it back?

Some games allow adding motion blur, but it still doesn't get close to the experience of a higher frame rate.

I think the problem is actually the opposite. In real life if you follow a moving object with your eyes then you expect its image to stay at a consistent place on your retina with no or minimal motion blur. If you follow a moving object on a typical LCD screen with your eyes, then for 30fps the object stays still for 1/30 s on the screen, while your eyeballs are still moving, causing motion blur on your retina.

Reply on news.ycombinator.com