Dynamic Contast Ratio...what's it mean?

[snafubaby]

I've been in the market recently to buy an HDTV. I know in years past you had to choose between Plasma and LCD. THEN you had to choose between HD and FULL-HD (720 and 1080). THEN you had NEW technology in LED tv's. Now, i notice the Dynamic Contrast Ratio on tv's. I know it's important because there is a big time price difference between 2 Vizio 47 inch full-hd LCD tv's at Walmart, where one is $767 or something, and the other is over $1000.

So my question. What is Dynamic Contrast Ratio? I saw one tonight on a 47" Vizio tv that is like 1,000,000:1. That's the highest i've ever saw. What does it mean?

[guns1inger]

The numbers are bullshit. There is no standard, so no objective way to compare the numbers from different manufacturers. Consider it nothing but marketing.

Dynamic Contrast Ratio means that the difference between the lightest and the darkest parts of the image being displayed can be adjusted on the fly, usually by altering the light values behind the screen. Cheap TVs don't offer this because there simply isn't enough lights to make a difference. Better TVs have more lights and better control, and good LED lit screen can alter the lighting values in much smaller areas, giving the best contrast of the lot.

I have started to see LED LCD screens boasting contrast ratios well over the million to one mark.

Personally, unless it is a 26 or 32 inch I would not consider anything under full HD, and if you can afford it, go LED backlit (Samsung would be my first choice, followed by Sony)

[jagabo]

Dynamic contrast means the difference between the lightest and darkest shades the TV can display. And it does not mean at the same time. The lightest measurement could be taken with the backlights turn up all the way, displaying a bright white picture, while sitting on the surface of a supernova. The darkest shades could be taken with the back lights turned all the way down, maybe even with the TV turned off, buried in a salt mine 6 miles below the surface of the earth. Good luck finding out how the manufacturer specifies how those measurements were take.

The ANSI static contrast ratio is take by measuring with the TV displaying a black and white checkerboard pattern (usually with the backlights turned up all the way) -- ie both the lightest and darkest shades are measured at the same time. But even this is of limited usefulness because most TVs can display adequate static contrast ratios these days. Normal viewing is usually down with the backlights turned down from the max. Unless you have the TV sitting outside in direct sunlight.

If you watch TV at night with the lights turned down what you really want to know is how dark the darkest parts of the picture can be (ie, the "black level") with the lightest parts at a normal (for that environment) viewing brightness. This is hardly ever specified.