Quote:
Originally Posted by JD Gumby
Despite what some would have you believe, refresh rate DOES matter on LCD screens for many people. Believe me, I can tell the difference between 60Hz and 75Hz on my LCD monitor within seconds due to the eye fatigue/strain starting to set in almost immediately at 60Hz, and the headache that invariably begins within a half-hour (if I don't take regular breaks from looking at the screen).
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Sorry, didn't mean to imply that flicker on every LCD was a myth. What I meant to point out was that if the data to the LCD panel is digital (ie: most laptop screens, tablets, cellphones, HDMI and DVI-D inputs on TVs and monitors) you will not see refresh flicker, even at low refresh rates of 60Hz. Being digital, once a pixel is set to say, white (digital 255,255,255), it will stay white before, after and during a refresh cycle until it is told to change. Even watching full screen video at 30fps, in most cases not pixels change at the same time and in a big enough area to see a flicker. This is, of course, dependent on the quality of the LCD panel and controller - there were some systems way back when that were advertised as 24bit colour displays (early Toshiba Satalite series laptops in the Win95-98 days) that where really 16bit colour which dithered the colour every refresh.
If the data is analog (VGA, DVI-A, S-Video, composite, whatever) then yes, you will see a refresh flicker because due to the uncertain nature of a analog signal, almost every pixel changes slightly every cycle. For VGA, there is a difference of ~2.5mV between colour levels. In worst case scenarios (for cheap panels), the pixel is blanked by the controller before being redrawn.
Good test for displays: Take a long a camera capable of shooting video @ 30fps. If you see dark bands moving on the screen, try another display if you are susceptible to eye strain.