A few of the latest compact digital cameras now feature super high speed continuous shooting. When you record a movie at 1000 frames per second and then play it back at normal speed, what you get is super slow motion. We’ve all seen ad nauseum videos of water drops or milk drops hitting the water surface — and they are cool! But a cube of jello hitting the table is even cooler — and much more fun! Just watch this:
From Goldtop23
For all you Science Geeks, describe what is happening at the moment of impact and beyond.
Understanding How Slow Motion Works
When you record a movie, you do so at a certain frame rate, which is simply a fancy term to mean how many frames (or pictures, since a movie is just a series of still pictures) are recorded every second. Most compact digicams will record at 30fps (fps = frames per second). Our eyes can roughly see 24fps and that is why movies are usually recorded at 24fps (“cinematic” rate). Anythnig faster and our eyes cannot make it out properly: “it’s so fast, I missed it!”
So, how do they do all those cool slow motion shots in movies?
Easy! Instead of recording at 24fps (or 30fps on our digicams), record the action sequence at a much faster frame rate and then play it back at the normal 24fps frame rate.
Here’s how it works. Let’s say you jump in the air and it takes you 2 seconds to do that. At 24fps, the movie camera takes 24 frames (pictures) in the first second, another 24 pictures in next second, for a total of (24 x 2 =) 48 pictures of you from the moment you leave the ground to when you reach the highest point.
When you play that back at 24fps, the 48 pictures take exactly (48 / 24 =) 2 seconds to show you jumping up into the air.
But what if you record the jump at 1000fps instead? That’s 1000 pictures every second of your jump for a total of (1000 x 2 =) 2000 pictures! [And yes, it takes up a whole lot of memory card space.]
Now, when you play that back at the normal 24fps, the 2000 pictures now take (2000 / 24 =) 83.33 seconds to show you jumping into the air. What should have taken only 2 seconds to show now take almost 84 seconds in excruciatingly glorious detail — super slow motion achieved!
Scientists use slow motion film to study all kinds of fun stuff, such as how birds fly and how everyday objects react to force, such as in car crash safety tests. These events usually happen too fast for our eyes to distinguish what exactly is happening, so slowing them down allows us to study what is happening.
Check out the Related Links for examples of digital cameras with high speed capability.
Related Links:
- Fujifilm FinePix HS10 (Super High Speed movie capture at 240 fps, 480 fps and 1000 fps)
- Samsung TL350 (maximum video recording speed of 1,000 frames-per-second)
- Samsung HMX-S15BN (600 fps)
- Canon SD4500 IS / IXUS 1000 IS (240 frames-per-second)
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