"Go ahead. Tell me you can distinguish individual
frames of a TV signal. 30 FPS is fine as long as
you make your camera (or rendering engine) act
enough like a human eye."
A NTSC TV signal provides two fields each displayed at 30 fps and interlaced. When
horizontal lines of high contrast are next to
each other (such as a single white line on a
black background) this is perceived as flicker.
Now consider whats happening: the phosphers along
that line are bright then gradually go dark until
the electron beam swings back to light them up
again. If 30 fps were enough, the eye wouldn't
notice this and we wouldn't perceive flickering.
Yet the average person does.
Try a simple experiment: change the refresh rate
of your display until you notice no flicker. For
me, this is at about 75 hertz.
For reference, flourescent lights flash at 120
hertz an even this bothers some people.
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A NTSC TV signal provides two fields each displayed at 30 fps and interlaced. When horizontal lines of high contrast are next to each other (such as a single white line on a black background) this is perceived as flicker.
Now consider whats happening: the phosphers along that line are bright then gradually go dark until the electron beam swings back to light them up again. If 30 fps were enough, the eye wouldn't notice this and we wouldn't perceive flickering. Yet the average person does.
Try a simple experiment: change the refresh rate of your display until you notice no flicker. For me, this is at about 75 hertz.
For reference, flourescent lights flash at 120 hertz an even this bothers some people.