Wednesday, April 15, 2015

Choosing or Buying Guide for projectors


Portable :
Sizes range from small and light enough to fit in a shirt pocket to suitable for permanent installation only. Most projectors fall in the middle: light enough to carry, but not necessarily light enough to go with you on every business trip. You may not mind carrying a 2- or 3-pound projector at all times, but you may consider a 10-pound projector worth taking with you for special occasions only.

What Resolution Do You Need?
Ideally, you should match the projector's native resolution (the number of physical pixels in the projector's display) to the resolution you use most often. Projectors can scale images up or down to their native resolutions, but they sacrifice image quality in the process. You should also consider the kind of information you'll be projecting. For a typical PowerPoint presentation, SVGA (800-by-600) will save money compared with getting a higher resolution. If the presentations will include things like spreadsheets, consider XGA (1,024-by-768) to show more detail at a time and still ensure that it's readable. For still more detailed images, like engineering drawings, you'll want even higher resolutions.

Do You Need a Widescreen Format?
Projectors with native widescreen resolutions are becoming more common. If you create your presentations on a widescreen notebook or monitor, they may look better if you project them in a widescreen format as well. Be aware that widescreen resolutions vary, however, so make sure you check that the actual pixel count of your computer and the projector resolution are a match. WXGA, for example, could be 1,280-by-720 or 1,366-by-768.

How Bright Should It Be?
There is no one best level for brightness, and brighter isn't always better. The best level depends on the amount of ambient light, the size of the image, and even the screen you're using. As a rule of thumb, for a portable projector to use in well-lit locations, 2,000 to 3,000 lumens is the right range. If you're setting up the projector in your own office, however, keep in mind that too bright an image is hard on the eyes. Buy from a knowledgeable source that can help you match brightness to the lighting conditions and screen in the room.

Keep in mind, too, that small percentage differences in lumens—2,000 versus 2,200 for example—aren't terribly significant. Perception of brightness is nonlinear in nature, which means you need far more than twice as many lumens to appear twice as bright.

Don't Take Contrast Ratio Too Seriously
Contrast ratio is the ratio in brightness between the brightest and darkest areas a projector can produce. All other things being equal, a higher contrast ratio indicates more vibrant, eye-catching colors and more detail showing in dark areas on the screen. Because other factors are also involved, however, knowing the contrast ratio doesn't really tell you much.

How Do You Plan to Connect?
Most projectors offer at a minimum an SVGA (analog) connector for a computer and a composite video connector for TV signals. If your computer has a digital output (typically a DVI or HDMI connector) you might want a digital connection on the projector as well, since it will eliminate any chance of problems like jittering pixels caused by poor signal synchronization. Most projectors today, however, offer rock-solid images even with analog connections. Keep in mind, too, that many notebook computers don't offer a digital output, so you may need to use an analog connection even if the projector has a digital connector.

What Technology Do You Want?
Today's projectors are based on one of three technologies: DLP, LCD, and LCoS. Most DLP business projectors project their primary colors sequentially rather than all at once. This leads to a rainbow effect, with light areas on screen breaking up into little rainbows for some people when they shift their gaze or something moves on screen. Those who are sensitive to this effect can find it annoying. LCD projectors don't have this problem, but tend to be bigger and heavier than their DLP equivalents. The general consensus is that LCoS projectors offer the best quality images, but they tend to be even bigger and heavier than LCD projectors, and far more expensive than either of the other two types.

Do You Need Audio?
Not all projectors include audio, and in those that do it's sometimes all but useless—particularly with highly portable projectors. If you use sound in your presentations, make sure that the audio is both high enough quality and loud enough to meet your needs. Alternatively, consider using a separate sound system.

Do You Need a Big Image in a Small Room?
Finally, consider whether you need a short throw—meaning the ability to cast (aka throw) a given-size image at a short distance from the screen. Short-throw projectors let you throw a large image in tight spaces, and also minimize the risk of people getting in front of the projector and casting shadows. There are no universally accepted definitions for what counts as a short throw, but as an example, where most projectors can throw a 2-meter-wide image from roughly 12 to 15 feet, most short-throw projectors need 3 to 6 feet, and ultra-short-throw projectors need only inches.

A wide and ever-growing range of business projectors are available, but you needn't get overwhelmed by the variations. Once you understand what differentiates them, you're sure to find at least one, and more likely several, suitable models to choose from.

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