With the digital TV transition fading fast in our rearview mirrors and market forces thinning the herd of competing technologies, buying an HDTV has become easier. Even better, prices that were once stratospheric have come crashing to earth. That said, those new to HDTV have some decisions to make when shopping for a new TV, not the least of which is what type of HDTV is right for them.
We've split our television category into several separate reports. Four of those reports discuss the different types of HDTVs in depth: plasma TV, LCD TV, rear-projection TV and front projectors. Our report on conventional tube-based televisions discusses standard-definition choices that still use that older technology. Despite challenges presented by digital reception, there's still a place for portable TVs, and those are covered in their own report. LCD TVHere, we've highlighted some of the important things to know about HDTV in general and describe the differences between the competing technologies. When you decide which type of TV you want, check out our other reports for the best choices.
Among HDTV types, LCD TVs offer the most variety. They come in a wide range of sizes, starting out at just a few inches and going as big as 75 inches (diagonal). Most are wall-mountable, and some are incredibly thin -- less than an inch in depth. The newest type of LCD TV uses an LED backlight, leading some to refer to them as LED TVs, though that's a bit misleading. In any event, LED technology allows for the best blacks and thinnest profiles of any LCD TVs, as well as the highest energy efficiency of any current TV technology.
Plasma is the other flat-panel TV technology. Consumer plasma TVs currently start at 42 inches and top out at around 65 inches, though a few professional plasma monitors in larger sizes are available. They are wall mountable as well but can get quite heavy compared to LCD TVs. Plasma sets are not as thin as LED TVs, nor as energy efficient. Once offered by a variety of manufacturers, only Panasonic, Samsung and LG remain as top-tier makers of plasma TVs.
There are a number of factors that could make either an LCD/LED or plasma flat-panel TV the right choice for you. While experts say the gap is closing, plasma TVs are known for their ability to display dark colors and detail better than LCD. This makes plasma a good choice for movie watching, where dark scenes are common. LCD TVs are brighter, which means LCD may be a better choice for a well-lit setting; plasma TVs can sometimes look washed out in a bright room. However, some LCD TVs with LED backlights can produce black levels that rival those of the best plasma TVs and clearly outperform lesser models. On the downside, LED TVs are more prone to issues with screen uniformity (some areas of the screen will be lighter than others) and blooming (light from brightly lit pixels will bleed off into dark areas surrounding them).
There are two types of LED TVs -- edge lit and full matrix -- and both have advantages and disadvantages. Full-matrix LED TVs when paired with a technology known as local dimming (the LEDs behind individual pixels or groups of pixels can be turned off) produce the best blacks. However, edge-lit LED TVs are the thinnest type and are generally less expensive. LCD TVs with conventional cold-cathode fluorescent lamps (CCFLs) remain available as well, and some are excellent budget choices.
Plasma screens have wider viewing angles than LCD flat panels. That means you can sit at more of an angle and still get the best picture. LCDs can sometimes leave trails behind fast-moving parts of an image. That's because of the time it takes for LCD pixels to switch color (plasma pixels make the change much faster). Also, slower LCD switching speeds sometimes cause a loss of detail in fast-moving images. However, technological improvements have made motion trails less of an issue in better LCD sets. Many better LCD sets also boast higher refresh rates (how often an image is repainted on the screen) of 120 Hz or 240 Hz. This technology is intended to address softness in action scenes. Some say it helps. Others say that while improvement in test patterns is obvious, there's no real improvement in watching typical programming, and any motion blur is more likely to be part of the signal itself than caused by the TV.
The most disconcerting issue regarding plasma TVs in the past has been a susceptibility to burn-in. Leaving the same image on the screen too long risked its being etched permanently into the screen, creating a lasting impression. New technology greatly reduces the risk of burn-in, and experts say that burn-in is no longer a major concern. Still, it's a good idea to turn off a plasma TV when you're not watching it. Temporary image retention -- a related but less severe problem -- is still a concern with plasma TVs, however, and some plasma TVs can maintain ghostly shadows of previously displayed static images for minutes or more. However, other plasma TVs include technology to minimize or completely eliminate temporary image retention. LCD TVs are not susceptible to either burn-in or temporary image retention.
Some less-expensive LCD and plasma TVs have a native resolution of 1,366 pixels by 768 pixels. TVs with that resolution can display standard TV, DVDs and 720p HD with no loss of detail, but they need to scale down 1080i HD programming and 1080p images from Blu-ray players. Manufacturers have been bringing 1080p sets to market in more screen sizes, down to as small as 19 inches. These TVs are more expensive than 720p TVs, but they can display every pixel of a 1,980-by-1,080-pixel HDTV image. Although initially more expensive than their LCD counterparts, prices for 1080p plasma TVs have dropped to the point where they are less expensive than most LCD TVs in similar screen sizes. Manufacturers are also continuing to produce 720p plasma sets, and these make great budget performers.
Thanks to the popularity of flat-screen LCD and plasma TVs, rear-projection TVs (RPTVs) have become an afterthought in the marketplace. Only one maker -- Mitsubishi -- is sticking with the technology, and it offers sets with screen sizes ranging from 73 to 92 inches.
Originally, four different rear-projection technologies were competing for floor space. However, all have given way to one -- digital light processing (DLP). DLP projection TVs direct light through a spinning color wheel onto nearly a million tiny mirrors that are used to project the image onto the screen. One problem with that technique is what's called the rainbow effect, which appears as a multicolored shadow around an object in certain scenes. However, only a very small percentage of the population can see these rainbows in the first place, and advances in technology have made it less of a problem. Even some of those afflicted say that an occasional rainbow doesn't bother them, but others say it wrecks the TV-watching experience and, in the worst cases, can cause eye strain and headaches. In any case, spending a bit of time auditioning a DLP set in a showroom might not be a bad idea.
TVs with rear-projection technology have a few other drawbacks compared to the flat-panel sets profiled above. For one, while they are nowhere near as large at the behemoths of a decade ago, rear-projectors are still relatively large -- you won't be hanging one on a wall, for example. Another is that they have a user-replaceable lamp that will burn out after a certain amount of time, and those lamps can be pricey. One Mitsubishi rear projector replaces the lamp with a laser. The primary purpose is notably improved picture quality, but the fact that there's no lamp to replace is a plus. However that projector is relatively expensive. For more information, see our report on projection TVs.
Once a part of only the most expensive home-theater setups, digital front projectors have dropped in price to where they are now a practical option. Although these projectors are capable of delivering the largest images (more than 100 inches) at the lowest cost (on a dollars-per-inch basis), critics say they are not perfect for everyone or every situation.
For one thing, they demand more from the user. To complete your home theater, you need to supply a screen (for best results) and an external audio system. Also, because projectors don't include their own integrated tuner, you need an external one or a signal from a cable or satellite TV box.
The second issue is light levels. For the most part, digital projectors are only suitable for use in rooms where lighting can be well controlled. That's because too much ambient light can wash out the image. This is less of an issue with brighter projectors. But still, front projectors are not the best choice for daylight viewing in a sunny room.
Front projectors using three different technologies are available. DLP front projectors have the same drawbacks (i.e. rainbow effect) as rear projectors, but they also have exacting placement requirements that can make using them difficult in some viewing rooms. Liquid crystal on silicon (LCoS) projectors are lauded for their great picture quality, but they are relatively expensive. LCD projectors offer great colors, but in the past were plagued with light black levels and an artifact known as screen-door effect, which causes a grid-like pattern to appear. However, advances in technology have boosted blacks to the point where they are competitive with other projectors and have essentially eliminated screen-door effect and most other drawbacks. Like rear projectors, front projectors rely on a lamp as a light source, and that will have to be periodically replaced by the user.
The biggest news in front projection has been the tremendous price cuts. Not long ago, a 1080p projector would have cost around $30,000. Today, a top-performing 1080p projector can be had for less than $2,000, and very good ones can be less than $1,000. Budget-friendly 720p projectors are also available. For the full lowdown on the best choices, see our report on projectors.
There's no shortage of places to read about HDTVs. CNET reviews lots of HDTVs and offers good detail without overwhelming those with less technical expertise. Those that want all the geeky details, however, might find the reviews at TelevisionInfo.com more satisfying. ConsumerReports.org is another prodigious reviewer of HDTVs, but discussion is short. Enthusiast sites and publications such as Home Theater Magazine, Sound + Vision Magazine, The Perfect Vision and others are also helpful. For front projector reviews, there are no better destinations than ProjectorReviews.com and ProjectorCentral.com. Amazon.com is a good spot for reading user reviews.