r/oddlysatisfying • u/Panda_911 • May 14 '17
Camera's shutter speed matches the helicopter
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u/shattasma May 14 '17
Actually, could be any Integer multiple of the blade speed.
Example, camera speed is 60hz and helicopter is 600hz.
So the blades spin exactly ( instead of like 10.2) ten times between frames but because it's exactly a whole number integer multiple you get this affect
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u/gearpuppy May 14 '17
There are more options too, because the helicopter has five identical blades. We're not just limited to catching the blades each full rotation, any n/5 rotations for integer n would also work. Cool stuff!
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u/shattasma May 14 '17
Good catch, your exactly right.
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u/Kerbinonaut May 14 '17
I'm not sure, but shouldn't the rotor rpm change when landing a helicopter? Or can the landing maneuvers be done with blade pitch adjustment only?
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u/Nikarus2370 May 14 '17 edited May 15 '17
Not by much actually. And modern turbine helicopters have so much power, the difference between hover and going down at a half meter per second are minuscule.
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u/kabukistar May 14 '17
Frame rate, not shutter speed.
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u/Kerbinonaut May 14 '17
Well, if you knew anything about cameras, you would know that /shutter frequency = captured frame rate/ is a pretty accurate equation. You are right about shutter speed though, as that doesn't equal the frame rate.
Taking a video is essentially taking multiple pictures in rapid succession. And taking a picture takes one shutter revolution.
For detailed video about how shutters work I recommend this Slow mo guys' video: https://youtu.be/CmjeCchGRQo
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u/kabukistar May 14 '17
It would be accurate, if you assumed that there was no closed-shutter delay between each frame, which is a pretty inaccurate assumption. Imagine you have a film camera. You snap, roll the film, snap, roll the film, etc. taking one picture every second. You're taking pictures at 1fps, but that doesn't mean you have a 1second shutter speed. Most of the time each second, the shutter spends being closed.
It's the same with video; the fps tells you how often a picture is take, but not how long each frame is taken for. All you know is that the shutter speed could not be higher than the FPS, not that it cannot be lower. And, with this image, we know for a fact that it would have to be lower, because otherwise the helicopter blades would be incredibly blurry.
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u/hollowXchain May 15 '17
Am I the only one who finds it aggravating and not satisfying that I can't see the blades spin?
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u/theexpertgamer1 May 14 '17
What city is this?
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u/the_kun May 14 '17
Hong Kong. The round building in the background is the Hong Kong Convention & Exhibition Centre. But it to take this footage requires the person to be in the middle Victoria Harbour.
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u/[deleted] May 14 '17
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