Sun, Jan 02, 2011 - Page 14 News List

Technology review

By Roy Furchgott  /  NY Times News Service, New York

Cho Hye-rim tries out a 3D LED television at Samsung Electronics Co’s headquarters in Seoul, South Korea.

Photo: Bloomberg

When most people buy a television, they measure the wall where they want to put it and then pick the largest screen that will fit. That is exactly the right way to buy a big TV, but it misses the point if you want the right TV.

The good news is that picture quality has improved radically in the past five years, even as prices have plummeted. The bad news: There are a bewildering number of specifications and features to consider. Many of them will matter only to hard-core videophiles, but some are critical to everyone.

One of the basic features is the type of set. Although projection and tube televisions are still available, most people choose either a plasma set or one of the two types of liquid-crystal display televisions.

Most of the professional installers I consulted prefer plasma televisions. And if you want a flat-screen model that is wider than 50 inches, there are few other choices.

The installers say that plasma sets have the smoothest motion, the truest blacks — more on that later — and are more easily watched from side angles than the liquid-crystal variety. Moreover, “plasma is generally cheaper,” said Shawn DuBravac, director of research for the US’ Consumer Electronics Association.

But plasmas also use more energy than liquid-crystal sets — making them more expensive to run — and LCD sets can work better in bright rooms because they have higher bright settings than plasmas. “The electricity cost of powering the TV, even for the largest models, amounts to less than US$2 a week [in the US],” DuBravac said. “That’s if you watch TV five hours a day, seven days a week.” The cost may not bother every customer.

There are also big differences among LCD sets. One technical distinction is that older LCD sets are backlighted by a fluorescent lamp, while the newer sort are lighted by hundreds of LEDs. These models can be brighter and have a higher contrast than their older cousins, and they are thinner, too — less than 2.5cm compared to 7.5cm or so.

LED screens tend to have better black levels than the older LCDs. The reason: Regular LCD sets create black by closing off a crystal, but light can still leak through — think of a cloth draped over a lamp. The LED variety, with its hundreds of individual lamps, can effectively turn off the light source — that is, click off the light rather than drape a cloth over it. But even that is not perfect. Although there are hundreds of lamps, there are millions of the pixels that make up the set’s picture, so a “black” area will still have a few lighted pixels. In plasma sets, however, the cells that make up the picture are lighted individually, making its blacks better still.

Resolution — the sharpness of the picture — is a second major factor for buyers. A few years ago, there was a complex variety of choices, but there are now just two — 720p or 1080p. (These terms refer to the number of lines on the screen, with anything higher than 720 considered high definition.)

Generally, 1080 offers finer resolution at a higher price, but that is not the end of the story because television broadcasts, DVDs and Blu-ray all enter the set at different resolutions. To make the number of lines from the source match the number of lines on the set, the television must use its computing power to scale the picture, and its ultimate quality will depend on how well the set’s computer and software do their jobs.

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