Xigga

Contrast ratio is the difference between the darkness and brightness (lightness). If you see an HDTV with a contrast ratio of 5,000:1, that means it can display 5,000 distinctive shades of gray, and that includes black and white.

So is higher contrast ratio better? It depends on what type it is. Manufacturers are now advertising Dynamic Contrast Ratio, which is not the actual contrast ratio of the panel. The panel’s contrast ratio might be 1,000:1. DCR adjusts each frame with some sort of algorithm to produce an image that is comparable to the frame if it was shown on a panel that had a 5,000:1 static contrast ratio. (By “panel” I mean LCD or Plasma screen).

How noticeable is it? Not very, because your eyes would need to see a DCR and a SDR panel side-by-side and a pitch-black room to notice it. Even then it depends on how sensitve your eyes are. To give you a quick lesson on physics (or biology), your eye’s perception of how bright an object is relative to other objects in the room. Let’s say you are in a room with the walls being completely black. You also have an omni-directional light source. You have several objects in the room which are different shades of gray. The lightest shade of gray will look white in that room. Now let’s paint the walls to super-white. Now that light-gray object will look gray to you because your eyes can only determine the brightness of an object relatively.

Also, if you are watching TV in a room which has a light source, which will most likely be the case unless you have a dedicated home theater room, it will be even harder to notice the difference in contrast ratios. Even in the dark, if you have light colored walls, some of the light will reflect back on to the TV screen. This doesn’t mean you shouldn’t ignore contrast ratios when buying a HDTV. They are important, but make sure you find out what the static contrast ratio is. You should look up the TV specs online and most of the time the manufacturer will have it listed on the website. Majority of the time it will be in the product spec sheet, which is usually in PDF format.

It’s not very easy to determine which TV will look better based on the DCR’s given. One TV maybe 10,000:1 and the other maybe 15,000:1, but it still depends on how well the second TV processes the frame. You should go down to your local retailer and have a look at the TVs. I haven’t been able to figure out what the actual algorithm for adjusting a frame with DCR is. My first thought was that it takes a frame and processes it to find how many shades it has. If it’s larger than the static contrast ratio of the panel, it “levels” the frame by shifting the brighness values down for each pixel. So if a frame’s darkest pixel is 500, it will set that pixel’s brightness to 0, and knock down the brightness of the other pixels accordingly. But it isn’t as simple as that. The only thing I was able to find about it is that it uses an algorithm called Iris, based on the eye’s iris, but that still doesn’t explain it. I have some further research to do…