It doesn’t make super-slow video if you play it back at the same rate at which you took it. But that’s not what happens.
Instead they take those 10,000 fps and they play them back at a much slower rate, generally something like 30fps. Because the playback is much slower than the rate it was filmed, this results in slow motion.
The reason you have to take such high frame rates is because if you just take 30fps video and play it back really slowly, you’ll get huge jumps between motion. At that rate, you won’t be able to see fast things like bullets at all.
Because it’s not played back at 10000fps, it’s played back at say 25fps, so it’s 400x slower.
120fps played on at 120fps is normal speed, played back at 60fps is 1/2 speed (2x slower), played back at 30fps is 1/4 speed (4x slower), 24fps is 1/5 speed (5x slower).
____
You film faster than normal such that when you slow down you have enough frames to not be jittery. On some low/medium budget movies, usually older ones, you can see that a lot of their slow mo shots where it’s not smooth at all and also decently blurry.
Let’s say there’s a car driving down a road at a fast speed, and you pull a camera out and take multiple pictures of the car and then play them in a slideshow.
The distance the car has traveled between the pictures will depend on how much time has passed between each picture you took with your camera. If you took a picture every five seconds, the car will have traveled a big distance between pictures. If you took a picture every one second, the car will have traveled a small distance. If you rapidly pressed the button and took multiple pictures a second, the car will have traveled a very small distance.
Now lets say you have super powers and managed to take thousands of pictures of the car per second. The car will have traveled pretty much zero distance between two pictures, and you will need to go through MANY pictures on your slideshow to notice a difference. If you scrolled through your slideshow fast, it will look like the car is moving in slow motion.
What a high speed camera is basically doing is taking thousands of pictures a second and grouping them together, and then playing through those thousands of pictures at regular speed when you watch them so that they appear to be a slow video.
Edit: changed my explanation a bit.
All video is just a bunch of photos shown in rapid succession.
We as a culture have decided that right around 25 frames per second (24, 25, 30, etc.) looks enough like “real life” motion to trick our eye into thinking it’s not just a bunch of individual images, it’s actually something moving.
If you take video at a higher frame rate, like 60 fps, and play it back at 60 fps, it looks even smoother, almost fake looking or something that we’re not really used to. If you take that 60 fps footage and play it back at 30 fps, it will look twice as slow. You’re playing those 60 frames back that took 1 second to record over 2 seconds.
Now instead of just filming at 60 fps, you record at 100,000 fps and play it back at 30 fps it’s the same thing, just MUCH SLOWER since each second is 100,000 frames long.
Stand somewhere with a lot of moving people, now close your eyes, once every 10 seconds open your eyes and immediately close them, do this for 60 seconds, you will see things have changed dramatically in between opening your eyes.
Now do the same thing, but make one change, open your eyes every second and immediately close them. You now see what is going on much more than the previous test, this is how frames per second on TV and film work.
Because it’s still played back at 24 (or 30) frames per second. If you played it at 1000fps, it would be in real time.
So it’s probably more correct to say that you /can/ play back film in slow motion – without having gaps, or losing information between frames – if you have a source recorded with much higher framerate. Than saying you’re filming slow-motion. Because you’re not filming slow-motion. You’re filming really fast, to play it back at a much slower pace than it was filmed at.
Replace the word frame with photograph.
Imagine you take 10 photographs of something in the space of one second and you put all those photographs together and make a video. You can play all 10 photographs one after another over the course of 1 second, or you could play them over the course of 10 seconds. If you did the latter, you’d have created a ‘slower motion’ version of the first video. Unfortunately though because you only took 10 photos over one second, over the course of a 10 second video there isn’t much fluidity between the photographs: a moving person in your video will appear to ‘jump’ between photos, or frames.
Now imagine you did the same thing, but you took 10,000 photographs in the space of 1 second and you make a video. Now when you show your 10,000 photographs over the space of 10 seconds in your video, your eyes are seeing 1000 photographs all one after another per second. The movement of anything in motion now seems fluid. You can of course play those 10,000 photos over the course of 10,000 years and it would then seem like a static image, save for the once a year the photograph changed.
Latest Answers