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Interesting article at Business Insider on why we don't like LED bulbs:
There's a handy trick for reading station signs that otherwise fly past in a blur as you travel in a high-speed train. Look at one side of the window and then immediately at the other side of the window. When you change your gaze, your eyes will automatically make a rapid jerking movement, known as a saccade. If the direction of the saccade is the same as that of the train, your eyes will freeze the image for a split second, long enough to read the station name if you time things right.
Saccades are very fast movements of the eyes. Their exact speed depends on the size of the movement, but large saccades can move the eyes at the same rate as a high-speed train. The image of the station name becomes visible because it is travelling at the same speed as the eye, and the images before and after the saccade are blurred and so don't interfere with the image of the sign. This shows us that our vision is still working when our eyes move rapidly during saccades.
Scientists used to think we could see no more than about 90 flashes of light a second but now we know it's more like 2,000 because the eyes move so rapidly when we change gaze from one point to another. During the eye movement, the flicker of light creates a pattern that we can see. And this has some surprising consequences for our health thanks to the way some types of lighting can affect us. In particular, it could discourage people from using more energy-saving LED lightbulbs.
Most lighting is electric and powered by an alternating current supply, which makes the bulbs continually dim and then brighten again at a very fast rate. Unlike filament lamps and to a lesser extent fluorescent lamps, LEDs don't just dim but effectively turn on and off completely (unless the current is maintained in some way).
The answer is not to make them less piercing?
(Score: 3, Informative) by theluggage on Saturday July 29 2017, @04:26PM
24fps doesn't mean the screen flashes at 24Hz - that would be horribly flickery. 24fps Movie projectors show each frame twice so that the "screen flicker" is 48Hz (https://en.wikipedia.org/wiki/Movie_projector#Shutter). The limitations of 24fps mainly show up as jerky motion (especially when the whole picture pans).
25/30fps TV does something similar with two "fields" per frame containing every other line of the picture. Shot-on-video Again partly because the full screen flickering at 25/30Hz would be annoying (at least on a CRT). Meanwhile, I'm pretty sure that modern TFT LCD screens don't blink on and off at 50-60Hz unless they have cruddy PWM brightness controls (I remember using 50Hz CRTs - they were only OK until you tried something better - then they were horrible!).
I think that's a genuine case of our brains misleading us because we're used to distinguishing "quality" TV programs shot on 16mm film (or processed to look that way) from "cheap" shot-on-video TV - which actually has smoother motion because it is recoreded at 50/60 interlaced fields per second rather than 25/30 frames per second.
I know that when I switched from CRT to a HD LCD TV with 100Hz framerate upsampling I was bothered for the first month or two because, although the picture was far better by any objective measure, it was firing the "shot-on-video daytime soap opera" receptor in my brain. It wore off after a while.
The other thing that got me was the switch from old-school curved "spherical section" CRTs to first cylindrical "Trinitron" CRTs then the newer "flatter, squarer tube" CRTs - for a while after switching to a new flat screen, my brain was so used to "correcting" for a curved screen that it applied the same correction to the flat screen, and I had the totally convincing illusion that the picture had horrible concave "pincushioning" (I actually had to hold a ruler to the screen to make sure it was actually square). Brains: awesomely powerful, but haven't had an OS update in a few million years...