by Bob » Mon Apr 25, 2011 11:49 pm
Contrast ratio is simply the ratio of the brightest to the darkest values that the display can produce. You would think that would be simple to measure and uniform across manufacturers. It isn't. There is no industry standard for how to measure contrast ratio. There are many ways to measure contrast ratio, and the results aren't comparable.
The best you can do is use the contrast ratio figures to compare sets from the same manufacturer and hope that they were consistent across their product line. If you are going to do that, use the "static" contrast ratio if they list it. It will be considerably lower than the "dynamic" contrast ratio that marketing wants to show you, but it will be more meaningful. "Dynamic" contrast ratio, in my opinion, is pure marketing hype. FYI, static contrast ratio is measured with the darkest and lightest areas displayed at the same time on screen, dynamic contrast ratio does not have that constraint -- you can even measure the dark area by turning off the backlight.
Take the contrast ratio figures with a grain of salt. The figures can be easily inflated by using brightness and darkness settings for the measurements that wouldn't work for normal tv viewing. The real test would be to view the tv and look at the detail in the darker areas. The better sets will display more detail and appear less muddy. With the current generation of LCD sets, unless you are buying a very cheap set, the contrast ratio will probably be adequate.