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So I was thinking of a cool video I could make when I thought of filming a video of me turning on a light. I thought that if you film yourself turning on a light and slo mo that video enough times (theoretically I you had a camera that could record that many frames per second)will you be able to see light moving through your videos view, or will it just turn into a slide show? Thanks in advance for any answers (PS if this has already been done please give me a link to the video.)

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  • $\begingroup$ How would you "see light moving" when the light has not yet reached you? $\endgroup$ – ACuriousMind May 14 '15 at 1:31
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    $\begingroup$ When the light goes through the frame of view $\endgroup$ – Aubrey Champagne May 14 '15 at 1:32
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    $\begingroup$ youtube.com/watch?v=yXHWJ4iUlZs. However this was done by repeating the light exposure a million times or so and taking photo shots at different exposure times. $\endgroup$ – image May 14 '15 at 1:36
  • $\begingroup$ @Marcel: Wow! That's cool! But now I want a femtosecond laser for christmas... $\endgroup$ – CuriousOne May 14 '15 at 2:35
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Light moves at about a foot per nanosecond, or a meter every three nanoseconds. In order to capture it propagating across a room over a few frames, you would need to gather something like a billion frames per second. No consumer camera -- indeed no camera on Earth -- is capable of this.

Now there have been people playing with "fempto-photography," but they use a hack. They switch on the light many, many, many times, in exactly the same way, and each time record just one frame at a very precise time. They then put all the frames into a single movie. That is, they leverage precision timing rather than raw speed, the former of which is achievable.

Note though that the equipment is still beyond the consumer level. You need a shutter speed fast enough so as to not blur a single frame, as well as nanosecond-resolution triggering.

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    $\begingroup$ The fastest camera I am aware of that can do single event recording is the Imacon 200 capable of recording 16 consecutive frames with 200 Mfps effective rate - you would see light move 1.5 m between frames... $\endgroup$ – Floris May 14 '15 at 12:23

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