Aspect ratio: The standard proportion in width to height for a computer monitor is 4:3, but some new displays have a wider format: 16:9 or 16:10, designed for viewing movies or HDTV in wide format. Note that a 17-inch wide-format panel has about the same vertical dimension and vertical
pixel count as a normal 15-inch panel, so you get about 120 percent of the viewing area of a 15-inch panel. A 17-inch standard panel, however, has 130 percent of the viewing area of a standard 15-inch screen.
Contrast ratio: A spec much hyped by manufacturers (be suspicious of their claims), this is the difference in light intensity between the brightest white and the deepest black.
Digital and analog connections: LCDs are digital devices and thus have to convert analog (VGA) signals before they can be displayed. A graphics card with a digital video interface (DVI) can send the signal straight to the display in digital format--no conversion required. Most LCDs come with an analog input (featuring a D-shaped connector that has 15 pins arranged in three rows, sometimes labelled D-Sub), some come with both, and only a very few come with just a digital input. Nevertheless, at this point, most monitors do such a good job of signal conversion that digital connections are not as important as they used to be.
Digital input |
Analog input |
Luminance: Brightness; a measure of how much light a panel can produce. Luminance is expressed either in nits or candelas per square meter (cd/m²). A measurement of 200 to 250 nits is OK for most productivity tasks; 500 nits is better for TV and movies.
Pixel-response rate: This refers to how quickly a
pixel can change colors, measured in milliseconds (ms); the fewer the milliseconds, the faster the pixels can change, reducing the ghosting or streaking effect you might see in a moving or changing image. In general, manufacturers' specifications rely on best-case scenarios; real-world performance could be slower. A maximum of a 12ms-to-15ms response time across the spectrum is required for gaming or viewing television and movies without ghosting or streaking. We've only just begun to see LCDs with superfast pixel-response times, such as
Samsung's SyncMaster 172X and
BenQ's FP767-12.
Portrait/Landscape modes: Some LCDs pivot so that the longer edge can go horizontal (Landscape mode) or vertical (Portrait mode). This feature can be useful for desktop publishing, Web surfing, and viewing large spreadsheets, but don't pay extra for it if you won't use it.
Portrait mode |
Landscape mode |
Resolution: Make sure you are comfortable with an LCD's
native resolution before you buy it. Remember, an LCD that scales its image to a nonnative resolution will never look as good.
Viewing angle: The physical structure of LCD pixels can cause the brightness and even the color of images to shift if you view them from an angle rather than facing the screen directly. Take manufacturer's specifications with a grain of salt and make your own observations if possible; viewing-angle issues become more critical as panel size increases.
