Introduction
There is wide range of technological choices available in multimedia projectors. But, that lets you make some general choices based on which technology is better and so on. The quality of the picture you depends on a number of factors and you should look at the important specifications of a projector in this regard. Brightness, resolution, contrast ratio are some of the most important specs.
Technology
The prevailing technologies in multimedia projectors are LCD and DLP. The newest kid on the block is known as LCoS or liquid crystal on silicon. LCD uses liquid crystals to pass light on or not depending on the input signal. When three such projectors are combined for the red, green and blue of color video signal, you get a full color projector. DLP or the digital light processor technology, on the other hand uses micro mirrors on a digital micro mirror device to project or or withhold light. In general, LCD projectors have a better color accuracy while DLP has a better definition of objects and does not allow pixellation to show up. Pixellation is the effect you see on a video where you get to see boxy areas when fast action is taking place. This could become a issue with the compressed video formats MPEG2 and MPEG4, which are in use today. LCoS is the newest technology and possibly provides the sharpest images with great color definition, but it costs a little bit more.
Brightness
This defines the light output. Depending on the distance of the screen from the projector, this spec tells you how bright the image would be on the screen. This is usually defined in ANSI Lumens and range from about 1000 to 3,500 or more. For home use, a brightness spec of 2000 to 3000 should suffice. The distance of the projector from the screen is an issue. While this spec applies to the light output just outside the lens, the brightness decreases as you move the screen further from the projector.
Resolution
This specification tells you how many pixels you can see on the screen. If you are planning to see full resolution HD DVD movies, then it is 1920 x 1080 resolution that you are looking for. Otherwise you can buy one with less resolution such as 1400 x 1050, 1025 x 768 etc. In this day and age however, you are probably better off buying the 1920 x 1080 product.
Contrast Ratio
This spec tells you the gradation of brightness difference between the darkest black pixel to the brightest pixel. It’s the ratio of luminance of the brightest white pixel to the darkest black pixel. Usually a dynamic contrast ratio is quoted. This is the capability of the system as it displays a changing picture, such as a movie. The ratio spec available varies in the range of 15,000:1 to 35,000:1. Projectors are available that can go up to 100,000:1. Generally the higher the ratio, the better the picture brightness range is.
Lamp Life and Recurring Costs
A bright lamp is the only recurring cost in the product life. You need to check out the life of these bulbs and the replacement costs. Typical life is 2000 to 4000 hours. That’s about one year of continuous use with about 8 hours use per day, just to put a perspective on it. They will probably cost you around $300 to $400 each time however. You’ll need a screen and cable kit too.
Selecting a Multimedia Projector
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