Life … moves … in … slow … motion … for … little … critters … like … flies

24fps *is* visibly jerky to humans; Cinema just covers it up

"At about 24fps, we humans see no flicker in a series of related images (aka a film ;) ) but a 12fps we can see the flicker."

Actually 24 to 30 fps *can* look jerky. This is partly covered up in cinema films by using a slower exposure time for each frame. The rule of thumb (AFAIK) is that recommended shutter speed per frame is half the frame rate. (*) Therefore, for 24 fps film, it would normally be around 1/48 second; enough to *blur* fast moving objects. This blurring is, ironically, intentional- it has the visual effect of smoothing the jerky motion. (**)

I have a DSLR that does video, but in bright conditions produces unpleasantly jerky results. This is because it automatically sets a much faster shutter speed to get the correct exposure, but doesn't account for the above. (If you look at each frame, there is virtually no blurring). If you can con it into using a slower shutter speed, the footage looks better.

Similarly, the reason why computer games apparently look bad at frame rates acceptable for film- 24 to 30 fps- is because they don't render motion blur. (Don't quote me on that though, I haven't personally been into games since the mid-90s).

(*) See the following for more information:- http://en.wikipedia.org/wiki/Rotary_disc_shutter

(**) Even so, you may still notice juddering on cinematic pans if you pay attention; you're probably just used to it. Cinema and film footage tends to use focus and depth-of-field to (e.g.) throw moving backgrounds out of focus on fast-moving pans. Traditional pre-digital video- AFAIK- generally has more depth of field and most cheap video productions can't afford to employ people to control focus, but they get away with it because video has a higher effective frame (or field) rate.

It would be interesting to research that, actually.

It certainly seems as though big horses react way slower than small ones to most rider cues, but they all react pretty fast if they perceive peril of some kind.

There is something else nobody has mentioned yet : obligations.

Children have none. Having nothing to do, they have all the time in the world (well, in the day) to think of something to do and act on it.

Adults have things to do. Be it work, repairs, shopping or whatever, a vast majority of our day is spent dealing with stuff even if we'd rather be doing something else. All that occupation certainly counts for some of that "time flies by" feeling we have, because we can measure our day by the stuff we did (or failed to finish).

That said, I do agree children always run to get places. Always.

Re: Time Perception.

Something has occurred to me: something related to the perception of time.

Perhaps our perception of time can be affected by state of consciousness, too. I once recall a few mornings when I was groggy, having just gotten up, and happened to look at the wristwatch I had at the time. I could've sworn I was seeing the seconds tick by pretty quickly, but by the time I was fully awake, things seemed to be normal again. Now, I knew time hadn't sped up while I slept, so I wondered if grogginess caused us to perceive time differently as well. Have there been experiments into the perception of time in differing states of consciousness?

Animals with faster reaction times than us lumbering humans are rather common. Felines, from the lowly cat to the majestic lion, have reactions that are seven times faster than ours.

You know about the laser trick for cats ? Shine a laser point on the ground and watch it go nuts trying to follow it (best results with young cats - older ones get bored quick). While you laugh, notice how the cat easily follows every jitter of the point with its head, even if it can't quite follow the movement of your hand as fast as you can wiggle it.

Yeah, you might have guessed that I love cats.

Re: Killing flies ...

Experience tells me they do go forward but can react to the air from your hand. I've found better success with a cupped hand. The wind forces are different, so the fly can't detect it as easily, plus it can catch the fly in a trap if they think the cup is safe (it isn't; when you slam down, you make a shockwave in the air trapped by your hand; said shockwave can be surprisingly effective on the fly even if you don't directly smash it). I've had some success swatting houseflies bare-handed this way. Also, try tensioning your arm so that you slam down as quickly as possible when you release.

Looks like a fish, moves like a fish.

Steers like a cow.

Re: For killing flies.....

I've seen them. They're really popular in Southeast Asia. Clear your room of skeeters and get some exercise at the same time. They're actually available in America, too, though I disagree with the prices.