A laser pointer at 2 billion fps makes the speed of light look... kinda weird
Why Hacker News recommends it
Referenced in threads about the two-billion-fps camera and equivalent-time sampling as an example of filming light moving.
What it is
AlphaPhoenix shows off a new camera that films at two billion frames per second and uses it to film a laser pointer pulse. He investigates a strange quirk in how the speed of light appears on camera.
Recommended by 0 HN commenters across 0 different months, 2025 to 2026.
What Hacker News said
Cites westurner · 2025-10 · on “Man Builds Two Billion FPS Camera That Records at the Speed of Light”
OT video: "A laser pointer at 2 billion fps makes the speed of light look... kinda weird" (2025; AlphaPhoenix) [this video]
Cites nomel · 2026-03 · on “From Oscilloscope to Wireshark: A UDP Story”
By definition, you can't interpolate a sample. A sample is a measured value. What you can do, if and only if you have an exactly repeating signal triggering at the same point within a cycle, is change the delay between the trigger and sample, and repeat. In other words, sample at different times within the same signal (since it's exactly repeating), to build up samples in time, of that waveform, to whatever time resolution you want. Of course, you're limited to any noise in the trigger, variation in the signal, etc. This is how you can record light moving through your garage [1]! [1] [this video]
Cites apt-get · 2026-08 · on “Using the railway network as a flatbed scanner”
Related - filming light at 2 billion fps with a somewhat similar setup in concept (at the single pixel scale): [this video]