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Start of Lightning Bolt Caught on Camera

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Re: Start of Lightning Bolt Caught on Camera

#31

a) overloaded site b) very nice, but is this "Hacker" News? More like Discovery Channel. How is this interesting from a tech point of view? High FPS cameras. Got it. Got it long ago.

"High FPS Camera" is a lot more impressive than the latest twitter-controlled todo-list app or whatever.

Re: Start of Lightning Bolt Caught on Camera

#32

I also like this 10,000 fps video [0] credited to Tim Samaras. [0] https://i.imgur.com/W1X1qFI.jpg

I was wondering how you could talk about a video and then link to a single image (I think jpg doesn't support animation). But it turns out all of https://i.imgur.com/W1X1qFI.jpg https://i.imgur.com/W1X1qFI.gif https://i.imgur.com/W1X1qFI.png link to the same GIF. :)

Ah good thing, so imgur abstracts extensions apparently

Better if you request with .gifv extension, then it's a much smaller (than a gif) html5 video)

Re: Start of Lightning Bolt Caught on Camera

#33

Earlier quoted context omitted.

I was wondering how you could talk about a video and then link to a single image (I think jpg doesn't support animation). But it turns out all of https://i.imgur.com/W1X1qFI.jpg https://i.imgur.com/W1X1qFI.gif https://i.imgur.com/W1X1qFI.png link to the same GIF. :)

Ah good thing, so imgur abstracts extensions apparently Better if you request with .gifv extension, then it's a much smaller (than a gif) html5 video)

The only issue with gifv is that if you open one on iOS it will pause whatever music you're listening to at the time. Kind of a bummer and something that will hopefully eventually get fixed.

Re: Start of Lightning Bolt Caught on Camera

#34

I also like this 10,000 fps video [0] credited to Tim Samaras. [0] https://i.imgur.com/W1X1qFI.jpg

I was wondering how you could talk about a video and then link to a single image (I think jpg doesn't support animation). But it turns out all of https://i.imgur.com/W1X1qFI.jpg https://i.imgur.com/W1X1qFI.gif https://i.imgur.com/W1X1qFI.png link to the same GIF. :)

I think that makes sense as I believe in their system the identifier will be

W1X1qFI which happens to be the url/filename and is auto-generated it ignores the extension

instead of throwing a 404.

Re: Start of Lightning Bolt Caught on Camera

#35

I also like this 10,000 fps video [0] credited to Tim Samaras. [0] https://i.imgur.com/W1X1qFI.jpg

I was wondering how you could talk about a video and then link to a single image (I think jpg doesn't support animation). But it turns out all of https://i.imgur.com/W1X1qFI.jpg https://i.imgur.com/W1X1qFI.gif https://i.imgur.com/W1X1qFI.png link to the same GIF. :)

For a second there I though they'd done something really clever with progressive jpegs!

Re: Start of Lightning Bolt Caught on Camera

#36
post #28
post #10

11k fps. Wow. I will never get tired of watching this stuff. That got me thinking, is there any theoretical limit to the number of frames that can be captured in one second?

The number of captured photons is a good hard limit. dalke's answer for ultrafast photography is kind of "cheating" in the sense that they record the same event periodically so they can gather enough light. That technique can't record single unique events that fast AFAIK.

No, it's not "cheating."

The title of my link says 'single-shot'. The underlying Nature article at http://www.nature.com/nature/journal/v516/n7529/full/nature1... says "Here we demonstrate a two-dimensional dynamic imaging technique, compressed ultrafast photography (CUP), which can capture non-repetitive time-evolving events at up to 10^11 frames per second"

Re: Start of Lightning Bolt Caught on Camera

#37
post #10

11k fps. Wow. I will never get tired of watching this stuff. That got me thinking, is there any theoretical limit to the number of frames that can be captured in one second?

Ultimately, sure, you run out of photons.

Let's start off with a baseline image resolution of 1 megapixel.

1 Joule is about 6E18 visible light photons, give or take. So that's then 6E12 photons per pixel.

Full sunlight on Earth has an intensity of around 1400 Watts (Joules/second) per square meter, or 0.14 Watts per square cm.

So achieving a frame rate in the trillions of fps would likely run into some limits relative to the size of your optics, the intensity of light coming from the scene, or the bulk quantum efficiency of the sensor.

And, of course, if you try to achieve quintillions of fps then you start dumping in nearly an entire Watt in photons into every single pixel on your sensor, which rapidly becomes a very big problem re: everything melting.

Additionally, modern electronics has trouble operating above the low GHz range, beyond that you'd need to move to superconductors or some such to keep up with the data.

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