What are the lines on a computer monitor when filmed on a camera?

If you've ever tried to film your computer screen, TV, or phone, you've likely caught a few flickering with black lines in frame.

By Gareth Mitchell

Asked by: Christopher Mercieca, Gozo

You’re probably thinking of the flickering seen when you film a computer display. The image on-screen refreshes at a different rate from the number of frames per second the camera records. Most computer monitors refresh in a range from 60Hz-120Hz; cameras work at 50 frames per second. Because camera and monitor are out of sync, you record fewer images per second, hence the flicker.

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