What about resolution? Digital projectors come in a variety of resolutions and aspect ratios. Native resolution measures the sharpness of the projected image and refers to a projector's true resolution without compressing the number of pixels (compression degrades image quality). SVGA (800 pixels by 600 pixels) and XGA (1,024 pixels by 768 pixels) digital projectors display images in a 4:3 aspect ratio. Some projectors, notably pico projectors, display images at VGA resolutions (640 pixels by 480 pixels) in a 4:3 aspect ratio.
Many portable digital projectors are widescreen models. These digital projectors are offered in a number of native resolutions. Projectors with WVGA resolution (854 pixels by 480 pixels) match the full resolution of DVD movies, so you get every ounce of a DVD's image quality. WVGA is loosely defined "standard" that also includes resolutions of 800 pixels by 400 pixels as well as 848 pixels by 480 pixels. In fact, any display that's wider than VGA can be classified as WVGA.
Some widescreen business projectors have WXGA resolution. WXGA is another non-standard standard that includes several different resolutions. For business projectors, 1,280 pixels by 800 pixels is a popular WXGA resolution since it matches that of many 14- and 15-inch laptop displays. That resolution can also display widescreen, high-definition images of 1,280 pixels by 720 pixels or 1,024 pixels by 768 pixels without cropping or scaling.
Consider lamp replacement expense in your long-term cost. Conventional digital projectors use lamps that must be replaced periodically. Average lamp life is between 2,000 and 4,000 hours, and replacement lamps aren't cheap. Some cost $300 and up. A few models of office projectors have long-life lamps rated to last longer. Although business projectors typically have warranties of a few years, most lamps are covered under separate warranties -- usually only for 90 days. If you don't want to hassle with replacing lamps, consider a projector that uses an LED light source. Many of these are rated to last 20,000 to 30,000 hours and should survive the life of the projector without needing replacement.
Will you need cables, speakers or a remote control? A projector's built-in speakers are usually unremarkable, but most projectors include audio ports so you can connect to an external sound system or powered speakers. Most projectors include basic cables, but some will leave out pricier options, such as an HDMI cable. Most projectors include remote controls; these can be either easy or difficult to operate depending on the model.
Use a projection screen for the best images. Projected images typically look best against a screen, though a light-colored wall will suffice, too. Decide if it's worth buying a screen and if you want to lug one around with you.
What about Rainbow Effect? All projectors that use DLP technology are prone to an artifact known as the Rainbow Effect, in that flashes of color are seen when a white object moves quickly across a dark background. The effect can only be seen by a small percentage of people, and a smaller percentage still is excessively bothered by it -- though some are bothered to the point where an image becomes unwatchable.