ELI5- why do screens/lights flicker in videos taken by phone or even yt vids, but not in movies and professional productions?
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Lights aren’t “turned on” without any pause. They all flicker a bit because of the electricity supply, but this flickering is too fast for our eyes to notice.
Every camera also does not record without any pause, it takes an image, then after some time takes another.
When the camera takes images faster than the time it takes for a screen to “shine then pause/rest then shine again”, then you end up seeing these on recordings as an annoying flicker; originally the reason cameras take so many images so fast is because the film gets very “smooth” and motion is captured in much more detail, but these annoying flickers from screens is the drawkback of this feature. Theoretically, there are 2 ways to avoid this: 1 you record slower (there are various ways to do this) so the flickering vanishes or 2 you give shorter pause /rest time for the screens. In practice obviously we go with scenario 1, because if you tamper with the electricity supply of the electronics by yourself, you could break it and even hurt someone.
Some light bulbs don’t necessarily flicker, because instead of rapidly turning off for a moment then on again, instead it faintly gets dimmer then brighter (you can do this with smart placements of diodes in the circuit to smooth out the electric supply to a relatively almost constant current; I believe more household light bulbs are made this way if you buy new generation, but I’m not sure) and the camera may not necessarily pick up this faint back-and-forth switches.
This is just roughly the theory to why you see it and how you could in principle overcome this. I don’t actually work in filming, so the current methods and solutions are definitely more smarter, but I don’t believe an ELI5 answer should reference anything too technical.
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