EmailExperts say that home theater projectors might not be the best type of HDTV for some, as they require low light levels for the best image quality, and there are lots of extra costs and requirements compared to LCD TVs and plasma TVs; see the ConsumerSearch report on those types of HDTVs for more information about them. However, home theater projectors also offer gigantic screens that are simply unavailable any other way and a true movie-theater-at-home experience. If you think that a home theater projector is right for you, here are some things to keep in mind as you shop:
- Figure replacement lamps into long-term cost. All projectors use replaceable lamps. Average lamp life is between 2,000 and 4,000 hours, and replacement lamps are not cheap. Most cost upwards of $250, and a few as much as $1,000.
- Experts say the image-quality gap between DLP and LCD projectors has closed. DLP projectors suffer from a phenomenon called the rainbow effect in certain images, but reviewers say it can only be seen by a small percentage of people, and the best projectors use a faster color wheel that minimizes it further. LCD projectors are prone to the screen-door effect, which means certain images appear as if they are being watched through a screen door. However, that's not much of a concern with 1080p projectors, and some models now use technology that eliminates the effect at normal viewing distances. DLP projectors have precise installation requirements that make them harder to place in a room than LCD projectors.
- HD projectors deliver the best home theater experience. Although home theater projectors with lower resolutions are available, experts say that the best home theater experience is obtained with a projector that's capable of displaying a 720p (1,280 pixels by 720 pixels) or 1080p (1,920 pixels by 1,080 pixels) HD image. In addition, some 720p projectors have a native resolution of 1,280 pixels by 768 pixels, which allows them to display full-frame computer XGA signals (1,024 pixels by 768 pixels) at their native resolution without cropping or compression. Projectors with 720p resolution remain significantly less expensive, but prices for 1080p projectors are dropping fast.
- Brightness and contrast ratio are important, but take manufacturer specifications with a grain of salt. Measured in ANSI lumens, screen brightness refers to the light thrown out by the projector. Contrast ratio refers to the difference between the darkest black and brightest white in a projected image. Projectors with higher brightness outputs are better able to handle ambient light and allow for bigger image sizes. A high contrast ratio means that the projector can create deeper blacks and show more shadow detail.
- Adjustable lens shift and a wide throw distance range allow for more installation flexibility. Lens shift refers to the ability to move a lens up or down, or right to left, to center the image on the screen without artifacts such as keystoning (a wider image at the top or bottom). Throw distance refers to the distance between the screen and the projector to create a desired image size. A fixed-lens projector has a fixed throw distance set by the manufacturer. A zoom lens lets the user change the throw distance to suit the installation, with wider zoom ranges providing the most flexibility. Almost all home theater projectors have a zoom lens. Many DLP projectors have either limited or no lens-shift adjustment.
- Consider the size of your room. Most projectors are capable of throwing an image of more than 100 inches (diagonally). That means you'll need to sit at least 10 feet away to get the best view. Obviously, projectors may not be the best choice for a smaller room.
- You'll get the best image if you buy a projection screen for your projector. A white wall can be used, but you won't get the best image quality and will lose brightness. Of course, a screen will add to the cost of your home theater. You can also construct a screen of your own with a few tools and some framing material.
- Factor in the cost of a home theater system. Most projectors don't come with an audio system. You'll need to hook them up to home theater system to get sound.
Projector basics
While they share many common characteristics, business projectors and home theater projectors serve very different functions and have very different audiences. For business users, projectors have mostly taken the place of the overhead projectors of yesteryear. Mobile professionals hook up a projector to a computer, projecting an image on a large screen or wall for presentations. The DVD player in your computer or a component DVD player can project movies or video demonstrations. Most business-oriented projectors weigh between 3 and 10 pounds, and usually come with carrying cases and wireless remote controls. The maximum resolution of business projectors is usually SVGA (800 pixels by 600 pixels) or XGA (1,024 pixels by 768 pixels), although widescreen business projectors with WVGA resolution (854 pixels by 480 pixels) are also available. See our separate report on
Budget home theater projectors with WVGA resolutions are available, and those are fine for watching DVDs or standard-definition TV, but reviewers say you should look for a projector that's at least capable of displaying a 720p HDTV signal at its full resolution (1,280 pixels by 720 pixels) if you want the best home theater experience. Some 720p projectors actually have a native resolution of 1,280 pixels by 768 pixels. Those projectors are also able to display full-frame computer XGA signals (1,024 pixels by 768 pixels) at their native resolution without cropping or compression.
The big news in projectors is that prices of models capable of displaying HDTV images at full 1080p resolution (1,920 pixels by 1,080 pixels) have fallen to the point where some are not much more expensive than 720p projectors. That means that 1080p projectors are now a consideration for all but the least expensive home theaters. See our separate report on
Home theater projectors don't have their own tuners (so they can't display television signals from an antenna), but they can display HDTV signals from a cable box or satellite receiver. Look for at least one HDMI input. HDMI connections are all-digital and are the preferred way to send high-definition signals from one piece of equipment to another. In addition, HDMI is compatible with HDCP (High-Bandwidth Digital Content Protection), a copy-protection scheme incorporated into Blu-ray Disc players and upscaling DVD players. An HDMI input is required to see images from those sources at their highest resolution and picture quality
Projector technologies: DLP, LCD and LCoS
When you start shopping for a projector, you'll immediately notice that there are two main projector technologies on the market: digital light processing (DLP) and liquid crystal display (LCD). A third technology, liquid crystal on silicon (LCoS), has now become well established as well.
Historically, DLP projectors boasted better contrast and black levels, while LCD projectors had better color saturation with less fan noise and lower operating temperatures. Because of improvements in both technologies, those differences have almost disappeared.
There are some other significant differences between the two technologies that could make one or the other more suitable for you. For example, LCD projectors still have a brightness advantage, but DLP projectors tend to be a bit smaller because the technology takes up less space.
DLP does have some significant disadvantages, however. Single-chip DLP projectors (all but the most expensive DLP projectors fall in this category) suffer from what is known as the rainbow effect. Because of the way these DLP projectors generate an image, a small percentage of viewers see occasional flashes of color. Only a small number of viewers are bothered to the point of annoyance by the rainbow effect, and most people aren't even susceptible to the phenomenon. However, until you try watching a DLP television, there's no way to know if you are affected.
In addition, many DLP projectors are finicky about where they are placed relative to the screen, making finding a suitable location trickier than with an LCD projector. Higher-end DLP projectors often incorporate lens shift, which lets users slightly reposition the lens up, down, right or left, which makes finding a good spot for the projector a little easier.
LCD projectors tend to suffer from what is known as the screen door effect -- images sometimes look like they would if you were viewing them through a screen door. However, advances in LCD technology have minimized the effect, and it is really not much of a factor in 1080p projectors. DLP projectors continue to handle fast motion better than LCD models. With LCD, blur or softening can be a problem with fast-moving objects in some scenes.
The third projection technology is liquid crystal on silicon (LCoS). LCoS technology debuted on top-dollar theater projectors and is now available in home theater projectors that sell for as little as $3,000. While there are still relatively few LCoS models, they generally fare pretty well in reviews thanks to their outstanding picture quality. Experts say LCoS benefits from great black levels and contrast, and freedom from the rainbow effect. However, motion blur can also be a problem with this technology and, while prices are dropping, most LCoS projectors remain significantly more expensive than other types.
Image size and brightness
Manufacturers usually specify a minimum and maximum image size for their projectors. Note that these are theoretical numbers that often have little to do with how an image will actually look. Typically, at the high end of the scale, the image will not be bright enough to look very good, while at the low end of the scale, images might actually be too bright.
For a projected image to look first rate, it needs to have sufficient brightness, which is defined by the Society of Motion Picture and Television Engineers as between 12 and 22 foot-Lamberts (fL), with an ideal of 16 fL. That recommendation is for a dark room such as a movie theater or a home theater room with good to great light control. You'll of course need a brighter image for a typical living room -- figure 25 to 35 fL.
Image brightness is determined by a number of factors, most notably projector brightness, screen gain, image size and the distance between the projector and screen (the throw distance). There are a number of good calculators on the Internet that do the math for you, making specific recommendations on optimal screen size. One of the best we've seen is at ProjectorCentral.com.
That calculator includes a database of almost every past and present home theater projector, though some of the very latest ones have not yet been added. The calculator lets you easily experiment with different throw distances and diagonal screen sizes to see how the two interact to influence screen brightness. It also reports other important information such as maximum room lighting levels for the intended use, recommended seating distances from the screen and more.
We used Projector Central's calculator to figure optimal screen size for the Optoma HD20, one of the projectors included among the Best Reviewed picks for this update. Of course, results will vary according to the lighting conditions in your room, screen gain and other factors. For an image brightness of 16 fL in a room with little ambient light (2 foot-candles or less), the Optoma HD20 will produce a 130-inch (diagonal) image at a throw distance of 15 feet, 6 inches; recommended seating distances are between 13 and 21 feet from the screen. The smallest recommended screen size in such a room would be around 110 inches, the largest about 147 inches. Rooms with higher ambient light will require using a smaller screen size. For a living room with some ambient light (around 3 foot-candles maximum) around 95 inches would look good; at 4 foot-candles, that size would drop to around 86 inches.