Life's frames per second

So how many frames per second does your brain really see in real life? It must be less than 24, or we’d really notice the film flicker. I think this was asked or mentioned earlier here, but I didn’t see the reply.

The reason you wouldn’t’ve seen a reply is because eyes don’t have a ‘framerate’ as there aren’t any frames! It’s as near to continuous as you can get.

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Guanolad is right. You’re probably referring to the retained image your eye (actually your brain) holds for a split-second after seeing something. It’s that retained image that allows movies and TV to appear continuous to most of us.
People with Alzheimer’s disease lose the ability to retain that image. They can actually see the flutter in film, TV and florescent lighting.

I think it would be helpful to point out that there is a big difference between the number of distinct images we can see per second, which is the closest thing to framerate, and the number of distinct images needed to fool our eye into perceiving them as moving.

The framerate is at least in the hundreds. We may not be able to do much with that, especially if quickly followed by another image, but we can make out an image even if it’s flashed for only a hundredth of a second or so. (It’s only in the jumble of a TV program that this isn’t noticed, where the idea for subliminal advertising came from.)

The question of the number of frames per seconds needed for video… It’s different in every medium, and depending on the type of picture. Computers, with crisply rendered images, have to display more in a second to get the illusion of motion. Film, with motion blur, makes it easier for us to be caught in the illusion.

Also, even though film works at 24, many studies showing that the higher the framerate, the more realistic it appears to an audience, suggest that film is only just good enough in the mid twenties, but that if we doubled the framerate, it’d look better.

So, even though that wasn’t an answer to your question, I hope it helped.

My photographer buddy says the answer is none, because frames is a unit of measurment for film without bearing to the question at hand.

Yer pal,

AH, I understood fps as sps, Stimulus/sec. We might not have got off on this persistence of vision thread tho. The nervous system works at damn near the speed of light.The 24fps is a compromise between ‘jerkiness’, cost of film,sound reproduction,strength of sprocket holes, readily available sprockets,gears,shutter mechanisms,electric motors(or easily maintained hand crank speed, etc. While the film is 24fps it is 72 Images per second as the projuector shutter opens 3 time per frame. 24 ips is too long the brain has time to register a still image.16mm and 8mm are 16fps, 48 ips. I discovered this when i was doing animation by hand cranking the projector when i saw the 3 flickers per image i took it as 3 frames per image, my animation was WAY jerky,after trial and error i stumbled on the secret,then i read a book which verified my results.I can’t discover what the fps and ips is for those super fast horizontal 72mm films, which might get us closer to the SPS of the human brains visual proccessor.( whoa, there is also a proccession of vision,but that’s a sequal)
I think the 16mm fps is correct while I was doing the animation I was doing something else too. I wasn’t worried about short term memory,somebody could remind me,and I figured it would be best to forget my checkered past anywy.

“Pardon me while I have a strange interlude.”-Marx

16mm and 8mm are 16fps,

actually all modern cameras and projectors operate at 24 fps, no matter what the size. the difference is in the feet per second since the film is a different size. 36 mm goes through as 96 fps (i think) whill 16mm goes thought at like 28 fps (or about). 24 fps has been accepted as the MINIMUM to see the program effectively, but other mediums, such as video play at 30 fps.

Perhaps you were using an older or specialized camera/projector.

I knew that degree in film production would come in handy sometime.

We live in an age that reads to much to be wise, and thinks too much to be beautiful–Oscar Wilde

whoops, i should clarify 96 feet per second and 28, not frames/sec

I agree with Guanolad that the issue/ metaphor of film frames is misguided. We are talking about neural impulses and chemistry that is much more complicated than videotape and the highest resolution screen.

(Sometimes I think it’s odd that we as a society have taken to comparing ourselves with Things we make–artifacts-- in order to understand ourselves: like the lecture you get in school about how your body is like a car, that needs fuel to run etc etc, or people talking about the hard disk and RAM in our noggins.)


I found this,tho it has nothing to do with Dave’s question about how fast the brain processes a visual image. (Let’s not get too pedantic we all knew what he meant.At least I took it as a visual stimulus per second, kind of, I think, maybe.)
Silent 35mm films were shot at roughly 16 frames per second (fps). The advent of sound standardized filming speed at 24 fps.
Most 35mm sound films are shot at 24 fps
Films shot in 16mm almost always run at 24 fps, with the exception of many silent home movies which are shot at 16 fps. {I was using an old WWII surplus 16mm silent Bolex} films shot for silent projection are usually photographed at 16 fps {that would be the pre-video Kodak 8mm homemovie cameras I was using}Different cameras provide different combinations of shooting rates.{the Bolex went from I think 8 to 48 or higher. The 8mm’s had a slowmo maybe 32}
Showscan™ uses 65mm film running vertically at a rate of 60 fps, whereas standard IMAX ™ , runs at 24 fps both use projector shutters which show each image only once.ALL i remember about the horizontal projectors is that they are horizontal because the film speed is so fast that the reels in order to hold enuff film are horiz. because they are so big. I saw one with 15 foot reels.They have to start slow and build up speed or SNAP! See who needs to worry about dead brain cells when we got the web? Sorry ,dave, can’t find anything about brain speed,except some herbs that will make it faster.And some wise guy saying that if the brain was as fast as light it would turn into energy.Least we know that a brain,maybe not Hitler’s , can process an image at least every 60th of a sec.MK,we gotta compare to something familiar,and the analogies work.I don’t know what else we could use.I’ve seen digestion compared to fire. I know I run smoother on high test single malts than cheap Scotch.Maybe I oughta pour some down this Mattel clunker’s hard drive.

“Pardon me while I have a strange interlude.”-Marx

What can induce a frame rate on perception is artificial lighting, which flickers in time to the alternating current powering it. It’s fast enough that you don’t notice, but if you spin a top under a light you will see the pattern come to a stop, then start to go backwards as the spin rate decreases. Under the sun, it doesn’t look like that.

Mr. John, am I miss remembering or didn’t the 16mm projectors show each frame twice.(I don’t have a clue what the fps was). I seem to remember working on 2 in the service playing a projectionist after hours and they did.
Oh, good times those were. Setting watching the movie, see the cue come up on the screen, run back to the projector room to switch projectors only to find the take up reel wasn’t working and the room was full of film.

jim,you are remembering fine. you were showing sound flics so it was 24fps ,two images per frame or each frame twice. I was using silent speed so 16fps so I got 3 . On the floor eh? I used to show some after hours in a small coffe house i ran,concrete floor often with spilled beer and who knows what on the concrete floor. Greg, flourescents and CRT"S are good strobes. But none of this is getting us any closer to the Frame rate OF perception.( I am gonna stay with that fps)
How fast does the brain process an image or a stimulus. is the processor as fast as the input? Is there a stacking function? I been looking all over the web and can’t find anything. BTW i am talking about the hman brain not mine. Mine is like one of those flip books.

“Pardon me while I have a strange interlude.”-Marx

Perhaps shedding light on the question, and perhaps not –

I’ve noticed that I can look out the window of a car on the highway, in daytime sunlight, and often the spokes on hubcaps of accelerating cars in the next lane will appear to stop, then start running backwards, as if I were seeing them under a strobe.

(I believe Cecil addressed this once in passing, but didn’t offer an explanation, merely confirming the observation of the poster who posed the question.)

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Oh brother, such an easy question, don’t people ever search the net anymore?

The human eye rate is 60fps.

I recall from my PDP class that the human neuron can fire about 2000 times a second, and the propigation isn’t really that fast. (One reason reflexes were developed.) So that would say that the upper limit of the human eyes frame rate would have to be 2000 frames a sec. However, the brain as a whole would have trouble processing that much information at once (2000 individual ultrahigh resolution images per sec, is an enormous amount of data to proccess.) So the eye uses several compression tricks before any data ever actually arrives to the brain. One trick is that the eyes ‘preproccessor’ only sends changed portions of the image to the brain (This is part of why persistance of vision exists). The brain receives a perodic ‘full refresh’ image after every eyeblink (Blinking, its not just to wet the eye anymore!) Also, the eye trembles, which causes the image to get a slightly larger delta to the image, and thus a partial ‘refresh’ which is larger than the normal. So, as someone said earlier, framerate really doesn’t corespond to the human eye, much like it really doesn’t corespond to an MPeg.

>>Being Chaotic Evil means never having to say your sorry…unless the other guy is bigger than you.<<

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I recommend every look at AHunter3’s post again. I have noticed this too, that spokes on a wheel can appear to stop, and reverse. This is impossible without some sort of “pictures per second” thing going on with your sight. And it should be possible to measure the speed with that too. Spin something until it appears not to move, find out what it’s revolutions per second is, and that is the hertz frequency that your eyes gather “frames” at.

A harder question. Is it scanning progressively, or a whole frame in an instant.

By the way, for those of you wondering how many frames per second it takes for computer rendered video to look realistic (not jerky), realize that it is not entirely related to your eye’s “frame rate”. In a real eye captured “frame” moving objects are blurred. The same happens with movie film and video. In current modern video games, moving objects are not blurred ito the frame, so even at rates higher than your eyes “frame rate” moving objects don’t have continuity and appear to hop choppily across the screen.

In addition, and in response to the OP’s assertion that “It must be less than 24, or we’d really notice the film flicker”. The blurring of each frame in film helps the eye not care about frame rate so much. One image blends nicely into the next, so it is happy. TV’s long burning phosphors help blur one image into the next keeping the TV’s image from looking choppy. But if we were to speed up film and TV’s sample rate, we would get to a picture that appeared clearer, as moving items would have less blur, but just as much continuity.

Handy, i was all over the web. It’s just that I didn’t know what I was looking for. “Human eye rate” At this place; I read, " Actually, the Human eye has a ‘refresh rate’ of about 60 frames per
second. You can test this by setting the refresh rate on your monitor to
60Hz or less, you’ll see it flicker out of the corner of your eye. " Which is about what I infered from my found hands on projector appraoach ( wasn’t as much fun as the thick soda thin beer can research) Ans Jeb, there’s your something to spin, somebody tell me how to set AND reset my monitor.From this I take it that 60 fps is the same as 60hertz? at least 60fps:eye::60Hz:crt but here; i read for the human eye; "max. frame rate ca. 15 Hz " so 15 fps? and “AIC delay 1 minute” I don’t know what AIC is, couldnt tell from the chart nor any acronyms i found ( Atlantic intelligence command? [I would wager they are always behind the event] Alice in Chains?[I don’t wanna know] )

“Pardon me while I have a strange interlude.”-Marx