As the title says im perplexed by this. Why, when i move my hand, under certain lights the movement looks nice and smooth. But under others it basically looks like my hand is moving at lower fps(?)?
This typically happens in a darker enviroment with very minimal lighting or in a place with dimmer lights.
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shitty lights that don’t properly smooth out the ac current they are being fed to drive the leds, so you have leds flashing with the ac power like a strobe light
Old incandescent bulbs made light by heating up a piece of wire until it glowed. The AC power that is switching back and forth at 50 or 60 times a second (depending on where you live) does it so fast that the change in the intensity of the glow cannot be perceived. LED lights only run at a few volts and to achieve this voltage, the power is turned on for a fraction of a second and then turned off for a bit longer. Since LEDs can turn on and off almost instantly this very fast flashing can be seen when there is quick movement. Higher quality LED lights have better electronics to help eliminate this problem.
This is also called the wagon wheel effect.
https://en.m.wikipedia.org/wiki/Wagon-wheel_effect
Cheap lights produce actually low FPS, effectively. LEDs are not constantly on, and rapidly dim or even flash 50-60 times per second, like a fast strobe light. Multiple overlapping sources can help reduce this effect
If the light flickers quickly, then you only see when the light is on (obviously). Your eyes aren’t fast enough to see the flickering, but you’ll still notice that movement looks choppy. You are, effectively, seeing reality in frames (though your eyes blur them together).
It’s called the stroboscopic effect and pops up in all sorts of weird places.
Indoor lighting using incandescent bulbs normally doesn’t have it, but LED lighting often has it. I first noticed it growing up around tube TV’s, which have a strong flicker to them.