Viewing Angles

LCD's produce their image by having a film that when a current runs through the pixel, it turns on that shade of color. The problem with the LCD film is that this color can only be accurately represented when viewed straight on. The further away from a perpendicular viewing angle, the color will tend to wash out. The LCD monitors are generally rated for their visible viewing angle for both horizontal and vertical. This is rated in degrees and is the arc of a semicircle whose center is at the perpendicular to the screen. A theoretical viewing angle of 180 degrees would mean that it is fully visible from any angle in front of the screen. A higher viewing angle is preferred over a lower angle unless you happen to want some security with your screen.

Response Times

In order to achieve the color on a pixel in an LCD panel, a current is applied to the crystals at that pixel to change the state of the crystals. Response times refer to the amount of time it takes for the crystals in the panel to move from an on to off state. A rising response time refers to the amount of time it takes to turn on the crystals and the falling time is the amount of time it takes for the crystals to move from an on to off state. Rising times tend to be very fast on LCDs, but the falling time tends to be much slower. This tends to cause a slight blurring effect on bright moving images on black backgrounds. The lower the response time, the less of a blurring effect there will be on the screen. Most response times now refer to a gray to gray rating that doesn't do the full on off state that generates a lower time than the traditional response times

Color Gamut

Each LCD panel will vary slightly in how well they can reproduce color. When an LCD is being used for tasks that require a high level of color accuracy, it is important to find out what the panels color gamut is. This is a description that lets you know how wide a range of color the screen can display. The larger the percentage of NTSC, the greater level of color a monitor can display. It is somewhat complex and best described in my article on Color Gamuts

Contrast Ratio

Contrast ratios are a big marketing tool by the manufacturers and one that is not easy for consumers to grasp. Essentially, this is the measurement of the difference in brightness from the darkest to brightest portion on the screen. The problem is that this measurement will vary throughout the screen. This is due to the slight variations in the lighting behind the panel. Manufacturers will use the highest contrast ratio they can find on a screen, so it is somewhat deceptive. Basically a higher contrast ratio will mean that the screen will tend to have deeper blacks and brighter whites.

Native Resolutions

All LCD screens can actually display only a single given resolution referred to as the native resolution. This is the physical number of horizontal and vertical pixels that make up the LCD matrix of the display. Setting a computer display to a resolution lower than this resolution will either cause the monitor to use a reduced visible area of the screen or it will have to do extrapolation. This extrapolation attempts to blend multiple pixels together to produce a similar image to what you would see if the monitor were to display it at the given resolution but it can result in fuzzy images.
Here are some of the common native resolutions found in LCD monitors:
17-19": 1280x1024 (SXGA)
20"+: 1600x1200 (UXGA)
17" (Widescreen): 1280x800 (WXGA)
19" (Widescreen): 1440x900 (WXGA+)
22" (Widescreen): 1680x1050 (WSXGA+)
23.6" (Widescreen): 1920x1080 (WUXGA)
23" (Ultra-Widescreen): 2048x1152 (QWXGA)
24" (Widescreen): 1920x1200 (WUXGA)
30" (Widescreen): 2560x1600

Service and support

The $599 price includes a three-year limited warranty that covers defects in the display and its peripherals. This also includes a 24-7 toll-free phone technical support as well as technical support through live Web chat. We could not find the drivers for this display on Dell's site. Under the support/drivers area on their Web site, this display was not listed at the time this review was written.

Features

The Dell UltraSharp 2408WFP includes an abundance of connection options. For video connections, you'll find a VGA, two DVI, an HDMI, a DisplayPort, component, and composite ports. There's also a speaker port, four USB ports (plus one upstream USB port), and a media card reader for Compact Flash and SD formats. That's certainly a long list of connections, but if we're being greedy, we would have liked to have seen an optical audio out connection. Compared with the lower priced Gateway FHD2400 we reviewed recently and praised for its connection options, the Dell surpasses it in the variety and volume of connection options. In particular, the extra DVI port and the DisplayPort are valuable extras if you want to connect the display to a media center or high-end PC.
The Dell has a Dynamic Contrast of 3000:1. This means--according to Dell--that the blacks the display outputs are three times darker than the whites are when viewing dark scenes. To get that kind of contrast ratio the display powers down its backlight in dark scenes, so that the blacks are very dark. This also means that if the dark scene in question contains areas of bright light, the light may be sacrificed as the backlight does not have the power to represent it accurately. Basically, Dynamic Contrast is just a marketing term and, for now, there is no independent standard for measuring it, so it should not be considered when making a buying decision. We felt the display was capable of dark blacks, but they could have been a bit darker. The whites were as bright as any we've seen in a recent display.