In the past few years, television has undergone a revolution. Thanks to high-definition TV, we can get unbelievably clear pictures. But choosing an HDTV set can be confusing.
High-definition refers to the resolution of an image. There are a couple of HDTV resolutions: 1,920-by-1,080 pixels (1080i and 1080p) and 1,280-by-720 pixels (720p).
You won’t notice much difference between 1080 and 720. Those numbers refer to the number of rows of pixels that make up the picture. Standard TVs display only 330 rows, which is a difference you’ll notice when you move up to HDTV.
The “p” means progressive, while “i” means interlaced. With progressive-scan HDTVs designated 720p and 1080p, the picture is refreshed all at once every 1/30th of a second.
With interlaced screens, which is what HDTVs labeled 720i and 1080i as well as regular standard- definition TVs are, the odd-numbered lines of resolution are refreshed first, then the even-numbered lines. Because they refresh the entire screen in a single pass, progressive-scan HDTVs offer a cleaner, smoother picture, which can help when viewing sports and other fast action. But overall, both progressive-scan and interlaced TVs are fine.
Signal conversion
Some HD signals are broadcast in 1080i; others are 720p. There are no 1080p signals yet. Your set will convert, or scale, the signals to match the native resolution of your HDTV.
To receive HD broadcasts, you need an HDTV tuner. Most sets include tuners, but some, called monitors, do not. If you have cable or satellite, you don’t need a built-in tuner. You’ll rent a tuner from the cable or satellite company. In that case, buy a monitor, if you can find one, to save money. To receive over-the-air signals, you’ll need a set with a tuner. You’ll also need an antenna.
There are different types of HD sets: projection, plasma, LCD and CRT. Each has disadvantages, but they’re all good.
Projection TVs are bulkier than plasma and LCD. You can’t mount them on a wall.
Projection sets are relatively inexpensive. Digital light processing (DLP) models are the most common type. You’ll also encounter LCOS (liquid crystal on silicon), LCD (liquid crystal display) and CRT (cathode ray tube). With DLP, you may notice a rainbow effect. Check the TV carefully before buying.
Plasma and LCD sets are wall- mountable. Both historically have had drawbacks, most of which have been solved or mitigated.
LCD sets are lighter than plasmas and consume less power. Until recently, they had problems with smearing – motion appeared blurry. Newer sets are less likely to have that problem.
Response time is important. That is the time it takes for the pixels to turn on and off. Aim for a response time of 8ms (milliseconds) or less. Smearing is less likely with fast sets.
Black levels
Black levels are sometimes a problem with LCDs. Gradations of black can be difficult to see in dimly lighted shows.
Smaller LCDs sell for well under $1,000. Larger models are more expensive than plasma sets.
Some consider LCDs superior to plasmas. But plasmas have beautiful pictures. The smallest plasmas are 37 inches. If you need something smaller, shop for an LCD.
Reflections are a problem with plasma sets. They work better in darker rooms. Historically, they’ve also suffered from burn- in. A static image displayed too long would become permanently visible on the screen. That is less likely with newer models.
CRTs range up to 36 inches. These look similar to traditional TVs. Many say CRT sets offer the best picture. But this technology is dying.
Why? CRT sets are massive. The tube can be 2 feet deep on large sets. Some weigh about 200 pounds.
HDTV prices are falling. If you’ve shopped for an HDTV in the past, look again. You’ll be amazed at today’s prices.
Contact Kim Komando at gnstech@gns.gannett.com.
