Originally Posted by big papa
does the PN50A550 have a 20,000:1 ratio or 30k? I am getting conflicting info from different sites. Can anyone tell the difference b/n 20-30k vs. the 15k that the FPT5084 has?
Frankly, contrast ratio claims are complete bullcrap. Here's why:
Let's say you have a display with "perfect black" - that means it is REALLY black when it is supposed to be black. It has a contrast ratio of infinity. Doesn't matter how bright the picture is or how dim, the contrast ratio will be infinity.
OK. Let's say the set will output 80 fL for 100% white and .01 fL for black. The contrast ratio is 8000:1 but the blacks aren't very black. If the set outputs 80 fL but blacks measure .001 fL, the contrast ratio is 80,000:1 but it's no brighter than before. But the blacks are much better.
Your eye can deal with contrast ratios of about 800:1 (some say it's closer to 600:1).
So you don't need high contrast ratios. What you need are black blacks to make images look good. But contrast ratio will not tell you how black the blacks are nor how white the whites are.
And another thing. White levels for plasmas change DRASTICALLY depending on how much of the screen is illuminated - fill the screen with white and you may not get more than 18 fL for 100% white. Put a "window" up that fills only 10% of the screen and you might measure 45 fL. The dirty secret of plasma manufacturers is that they use TINY white squares when they measure contrast ratio so they get the brightest possible white spot on the screen... many use a 4% window... meaning it covers just 4% of the screen, though some are trying to use a 1% window when they have meters that will measure that small of a physical spot on the screen. So contrast measurements are a boondoggle.
If you set the display to a REASONABLE luminance level, like 25 fL for a 10% sized window, you are limiting the peak light levels considerably... perhaps to 50% of what the panel is capable of for a 10% sized window. But if the blacks are really black, you'll still have an infinity contrast ratio. If the blacks aren't real black, you'll have something less than infinity and raising the luminance beyond 25 fL will make the contrast ratio larger, but you really don't want the picture any brighter than 25 fL anyway or you'll get a headache in a dark room after an hour or so.