Why do LED lights flickers when seen on film/camera?
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Normal old school light bulbs are also flickering. Often its usually because the power supply from the output changes its mind about the charge 60 times a second. You cant see the old school light bulbs flicker because the hot filament inside stays hot. Being hot makes it emit light even without power – for a little while!
LEDs don’t heat up. They make light by a different process and can actually turn off & on extremely quickly. Billions of times a second. So they can turn off as the electricity going to them cuts in & out 50 times a second. Also, electronics try to do ‘multiplexing’ as another poster mentioned here, but because LEDs are so responsive we can visually see when its not done fast enough.
A phosphor (not to be confused with Phosphorous, that chemical) is a special coating which illuminates when energy hits it from somewhere. Like an electron or even another light. Normally they’re quite slow to light up & go dim again. Very much like a light bulb Filament staying hot. Old school CRT televisions have this, white LEDs have this. Old school radars have one too (a very slow one, so you can see that BLeeep stay on the screen for ages).
Now coloured LEDs are more basic than white ones (monochromatic is the word). Red/blue etc will be EXTREMELY quick at turning on & off. A white LED actually has a tiny Phosphor coating which eats up light from a hidden blue LED behind it, and then glows as yellowish. It looks white to our eyes. (Its true!) But they are still extremely fast compared to a light bulb.
There are other kinds of lights too: Florescent lights (those tube things) They have yet another way of making light. They need to be stimulated with energy and then you gotta take the energy away. Its when the energy goes away they chill the F out and release a little bit of light. Do this repeatedly real fast and you can get them to keep emitting light, but they flicker.
Truth of the matter is those tube lights are capable of flickering much faster and being way smoother, and the headaches they’ve given people for decades have been avoidable this entire time. In fact, they’re more efficient when you do so. It just cost more money to build the electronics. And we all like to save money if it means we can give people headaches.
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