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Comment by chovybizzass | Hacker News Reader

how many frames per seconds are our eyes recording at?

Our vision is not frame-based at all. Each receptor cell can trigger inependently. Chopping up the signal into image frames is simply a technical trick that makes us perceive continuous motion due to the finite recovery time of the cells (persistence of vision).

I can't tell if you're joking, but in case anyone else is wondering: Most people can perceive between 30-60 frames per second. Some (mostly gamers) reportedly perceive up to 120 frames per second. Though whether this counts as recording is a matter for philosophers.

This is many orders of magnitude more than that.

Its wierd because I could differentiate between 120Hz and 240Hz but I think its because the computer generates still images without motion blur. So 120Hz with perfect motion blur would be indistinguishable from 240Hz I think

If only it were that simple! There's no-such-thing as 'perfect motion blur', it's all a matter of taste.

You can do things like open the virtual shutter to full-open (so that not a single virtual-photon reflected off the virtual-motion will be missed by the virtual-sensor), which makes the motion recorded during one frame continue directly (with no time 'gap') into the next frame. This can help make things seem 'smoother' for sure but it's still relying hugely on persistence-of-vision.

I'm super surprised (and a bit incredulous tbh!) to hear of a perceivable difference between 120 and 240fps! need to go double-blind on that stuff to be sure I reckon!

On a computer game you can spot the 240fps because of the intermediate frames when you have visual elements moving very quickly across the screen. It's not because of 'faster eyes' I don't think. Like when you move your mouse very quickly you'll see twice as many mouse cursors en route.

Afaik you can also detect images that are present for a millisecond (eg white screen with one black frame at 1000fps).

You can detect very small numbers of photons (sometimes a single photon), your eyes don't care about the frame rate. The question is, can you tell the difference between 120FPS and 240FPS

Still an excellent question! There's this (no proper references) that seems to suggest ppl lose the ability to make meaningful judgements about frame rate (or ~differentiate differences) after around 150fps:

https://www.quora.com/What-is-the-highest-frame-rate-fps-tha....

This (150>120) seems to suggest that many people would be able to see (maybe it'd be better to call it "feel" the difference at this point) the difference between 120 and 240fps. but they most likely couldn't tell 150 from 240fps.

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