What exactly is "Slow Motion"?

Slow motion. Something which amazes people.

Like this:

Except that it's not slow. This is made at 24fps and has 96 frames (4 seconds)

If we want to make it 8 seconds, we do some maths:

FPS    TIME

 24        4s
 12        8s (x2)


That means that we lose frames as we now have a 12fps video that is 8 seconds long. What do we do?

We double the fps back to 24fps. But how? In the real world, we would use a slow motion camera capable of recording over 24fps. So that when we stretch it out, instead of having 12fps, the frames we don't normally see fill in the gaps, bringing it back to 24fps.

So, if we shot at 2400fps and playback at 24fps, we get a 4 second video.

But, if we expand it out to get all 2400fps, we would get a (2400fps / 24fps = 100) times longer video, resulting in a 400 second (6.666 minute) video.

This is similar for even higher values, like 96fps or something insane like 24 * 10¹⁰


We just stretch out the video, and it goes back down to 24fps while increasing in length.

(Simple rate calculations, innit?)

So here's the previous video shot at 120 fps (Dammit blender you don't let me go at 2400fps)

Oh yeah thanks to SheepIt Render Farm for helping me push this video in just 5 minutes, instead of a whole night...