from Technology & Learning
There are a variety of factors to consider when finding the perfect projector. Pick your priorities.
A projector connected to your computer gives you the ability to share your screen with a classroom. You can display Web sites, show students' computerized presentations, provide large-group modeling of skills and techniques, brainstorm concept maps, play a video, or mark up the screen and save your notes.
Here are features to consider when choosing a projector, whether it's a liquid crystal display or digital light processing model.
A projector's brightness is measured in lumens. The least expensive projectors are usually the lowest in lumens (fewer than 1,000) and are designed for small rooms with the lights lowered. In general, more than 3,000 lumens are needed for auditoriums and other similarly large rooms, under normal light conditions.
Depending on the type of information you are projecting, different resolutions may be appropriate. For example, most PowerPoint presentations, as well as simple charts and graphs, project well at 800x600; highresolution graphics and small print may need as much as 1280x1024. Available projector resolution choices include VGA (480x640), SVGA (800x600), XGA (1024x768), and SXGA (1280x 1024). And remember—it is best to match the resolution of your laptop or computer to that of the projector. Typically, a projector will have a "native resolution" as well as "supported resolutions." The native resolution is that at which display will be optimal; supported resolutions are achieved by scaling the image, resulting in a loss of quality—a similar effect to enlarging a small digital photo to a larger size.
Size and weight
If your projector will stay in one room or be mounted, size and weight become less of an issue. However, if it will be carried then you may want to consider smaller, lighter projectors. Small projectors may be as light as 1 or 2 pounds, many are about 5 to 7 pounds, and some weigh considerably more. Smaller, lighter projectors can cost more or may not be as bright or have as high a resolution. Larger, heavier projectors may have additional features such as multiple inputs and outputs.
Projector lamps can be expensive, with some costing as much as hundreds of dollars, making lamp life an important consideration. A life of 2,000 hours is considered to be good. Certain projectors offer an economy or whisper mode (diminished brightness, lower fan noise). Also, remember to let the projector's fan stay on for several minutes after turning off the light so the lamp can cool down.
Inputs and outputs
In addition to the standard computer connection, projectors may also have ports for DVD players, HDTV, and VCRs. Some projectors come with audio inputs and outputs to receive sound, along with external speakers.
Zooming and keystoning
The projector's zoom lens may be manual or automatic and some are remote controlled. Keystoning refers to the image distortion that occurs due to the angle at which the projector is aimed (the image will appear as a trapezoid). Projectors may have a keystone correction mechanism built in to compensate for and correct the shape.
Projection distance refers to the minimum and maximum distance between the projector and the screen. A shortthrow projector has a very small projection distance and can be mounted on an arm attached to your whiteboard or screen. The benefit of a mounted short-throw projector is that it eliminates the wires and opens up more floor space. Some projectors have networking capabilities, allowing administrative management from a remote PC. Most projectors include a remote control; also the fan noise level can differ between projectors.
Jeffrey Branzburg is a contributing editor and columnist for T&L.
A guide to the latest in projectors.
This new DLP projector has a brightness rating of 2,600 lumens and XGA resolution. Weighing in at 6.4 pounds, it has an estimated lamp life of 2,000 hours, digital vertical keystone correction, and manual zoom/focus control.
Dell's small 2400MP DLP projector is a bright 3,000 lumens and weighs 5.5 pounds. It is an XGA projector with an economymode option that extends the lamp life from 2,000 to about 2,500 hours. It supports both horizontal and vertical keystone correction.
Canon's new multimedia LCD projector has a short-throw distance with the ability to display a 100-inch diagonal image from 9.2 feet away. It is a 3,000-lumen, XGA resolution projector with a full digital connection to DVD players and PCs and vertical keystone correction. It weighs 7.3 pounds.
ImagePro 8755 series
Dukane's most popular LCD projector for Kâ€“12 schools has been the ImagePro 8755 series, which includes the 8755G and 8755G-RJ (the RJ has a network port built in for projector-management capability). Both are 2,200-lumen, XGA resolution projectors that feature 7W audio. Each weighs 7.7 pounds, has a lamp life of 2,000 hours or 3,000 hours in whisper mode, and includes digital keystone correction.
Epson's PowerLite 77c is a 2,200-lumen, XGA resolution LCD projector. It offers keystone correction and an exceptional lamp life of 3,000 hours in highbrightness mode and up to 4,000 hours of lamp life in low-brightness mode. It weighs 6 pounds and has a 5-second, instant-on startup.
Learn Big IN2100 EP series
$499 and up
InFocus also offers a series of DLP projectors designed specifically for educators. The new Learn Big IN2100 EP series features projectors with 2,500 lumens, a 2,500-hour lamp life (3,000 hours in whisper mode), as well as digital vertical keystone correction. Each weighs 6.9 pounds.
Hitachi's CP-A100 targets the education and corporate markets with its 12.8-pound LCD projector that features brightness of 2,500 lumens and XGA resolution. Its short-throw capability allows it to be placed 1.4 feet from the screen and still project a 60-inch image. It can be placed vertically to project an image onto a tabletop or floor. Its networking capability allows for simultaneous monitoring and control of several projectors from a remote location. Other features include a lamp life of 2,000 hours or 3,000 in whisper mode, networking capabilities, and digital keystone correction.
The Mitsubishi XD470U is a 3,000-lumen, XGA resolution DLP projector with digital keystone correction. It weighs 6.2 pounds and has a lamp life of 2,000 hours in normal mode and 3,000 in low mode. It also has an instant shutdown feature.
NEC's VT800 is a new addition to its VT LCD projector line. It is a digital network-ready projector designed for education and corporate settings, offering 2,700 lumens and XGA resolution. It weighs 8.2 pounds, has a lamp life of 2,000 hours to 3,000 hours in economy mode, and automatic keystone correction.
Panasonic's PT-P1SDU LCD weighs in at 2.9 pounds. It also has an SD card slot, allowing it to project digital still images or video shots with a Panasonic Lumix digital camera as well as PowerPoint (the Panasonic Image Creator software converts the Microsoft PowerPoint file to a JPEG). The tradeoff? Brightness is 1,500 lumens and resolution is SVGA (800x 600, compared to XGA's 1024 x 768).
Toshiba's TDP-PX10U is a lightweight DLP projector, weighing 2.9 pounds. This 2,000-lumen XGA resolution model also includes digital keystone correction and a USB port for projecting presentations without a computer.
Sharp's XR-30X is a 2,300-lumen, XGA resolution projector, weighing 6.4 pounds. A DLP projector, it has a low power economy mode with a high-efficiency lamp that increases lamp life from 2,000 to 3,000 hours. It comes with a wireless remote with forward/back PC and mouse control.
How about a high-definition projector? Although primarily marketed for video use, the Bravia VPL-AW15 LCD handles computer input as well. This 1,100-lumen projector has vertical keystone correction, a 1280 x720 resolution, and weighs 12.7 pounds.
ViewSonic recommends its PJ557D, a 2,300-lumen, XGA resolution DLP projector, weighing 6 pounds. It has a manual zoom and focus control and is capable of displaying HD and video. Its economy mode extends the 2,000-hour lamp life to 3,500 hours, has vertical keystone correction, as well as the ability to project onto various display surfaces.
How light can you go?
The lightest projector I found is the Mitsubishi PK20 PocketProjector, weighing 1.1 pounds. Why was it not included in this review? Because its specifications put it below classroom effectiveness—only 25 lumens and 800x600 SVGA resolution—the PK20 is best for small group presentations and gaming displays but not the classroom.