Agora mais a sério: Imagine yourself watching movie of an unbelievably slow fog. You don't see edges and sharp borders. Now play the movie with 10fps. It will look fluid. Why? Because the difference from one frame to the other is very low. The extreme would be a totally unmoving wall: Then 1 fps would equal 1000 fps. O que tu falaste: Now take your hand and move it slowly in front of your face. Then move it faster until it's blurry. How many frames per second do you see? It must be little, because you see only a blurred hand without being able to distinguish every change per millisecond, but it must be many, because you see a fluid motion without any interruption or jump. So this is the eye's trick in both examples: Blurring simulates fluidity, sharpness simulates stuttering. Mais de 30fps no olho humano ? no way: The fact is that the human eye perceives the typical cinema film motion as being fluid at about 18fps, because of its blurring. If you could see your moving hand very clear and crisp, then your eye needed to make more snapshots of it to make it look fluid. If you had a movie with 50 very sharp and crisp images per second, your eye would make out lots of details from time to time and you had the feeling, that the movie is stuttering. Gaming: Just think of modern games: Have you ever played Quake with 18fps? There is no motion blur in those games, thus you need a lot of frames per second more. However, you see the spots and the dirt of single frames in a cinema film, don't you? And those movies are played at 24fps. So there is a difference between seeing motions fluid and seeing that there's something (dirt) at all. Conclusao...nao há conclusao: So what is "Enough fps"? I don't know, because nobody went there so far. Maybe 120fps is enough, maybe you will get headaches after 3 hours. Seeing framewise is simply not the way how the eye\brain system works. It works with a continuous flow of light\information. (Similar to the effects of cameras' flashlights ("red eyes"): flashing is simply not the way how we see). So there are still questions. Maybe you need as much as 4000fps, maybe less, maybe more. The same question as for fps will arise for resolution. How many pixels can the human eye see? Does 2000x1000 (=Star Wars Episode II resolution) look like reality? Or is it just enough to make a film "cinemable"?