Monitor technology
Panel technology
CRTs have effectively been replaced by their thinner and brighter sister, the LCD. Under the umbrella of LCD technology, there are a few choices to consider before buying a monitor. First, you'll have to decide which panel technology is right for you.
The three main panel technologies currently used in LCDs are: twisted nematic (TN), vertical alignment (VA), and in-plane switching (IPS). In 2011 we saw the debut of a new panel tech from Samsung called Plane to Line-Switching (PLS), which theSamsung SyncMaster S27A850D houses. Manufacturers make the vast majority of consumer monitors using TN panels.
Not surprising, TN panels are the cheapest of the three technologies to make. With a few exceptions, monitors that cost $300 or less will likely have TN panels. The main advantages of TN panels are their fast--usually 2ms--response time and, of course, low price. Their major disadvantages are narrow viewing angles, relatively low brightness, and inaccurate color reproduction.
Next up are VA (mostly known as S-PVA) panels. VAs have improved viewing angles compared with TNs, better color reproduction, and they typically have a much higher maximum brightness. Also, they tend to have the lowest black levels of all four panel technologies. Unfortunately, a VA panel's response time and input lag are not quite as fast as a TN panel, and they can cost anywhere from $400 to $800, and sometimes more depending on the panel's size. Also, you can expect a VA-based monitor's profile to be wider than a TN's.
IPS-based monitors are usually the most expensive; however, the new e-IPS panels cost as little as $300 when incorporated into a 22-inch monitor. They also tie with PLS for the best viewing angles of all the technologies and produce the most accurate colors; however, their blacks are not as deep as VA panels'. IPS monitors are the slowest of the bunch in both response time and input lag.
PLS is a new panel technology from Samsung that debuted with the Samsung Galaxy Tab 10.1 tablet, but the first monitor to make use of the tech was the Samsung SyncMaster S27A850D. PLS panels sport viewing angles as wide as IPS, while offering a higher brightness at a lower cost to power consumption. According to Samsung, production costs for PLS panels are 15 percent lower than that of IPS as well.
Backlight
Let's clear this up right away: LED and LCD technologies are not mutually exclusive. To ask what their differences are is like asking what the difference is between Vibram Five Finger shoes and rubber soles.
So let's break down what LCDs and LED backlights are, as they relate to monitors, and delve into the real advantages of LED backlighting technology.
The term LCD stands for liquid crystal display. LCDs are an upgrade (in most respects) from tube-based CRTs (cathode ray tube) from years of old, although some still prefer CRTs over LCDs. In short, LCDs use liquid crystals to express what you see on the screen. The crystals act as a shutter for the backlight, and, depending on the type of charge given to them by the monitor's built-in electrodes, the crystals will either allow light through to the user or shut it out, thereby allowing the pixels to express their appropriate colors, making up what you see on the screen.
LED-based monitors are still LCDs (they still use liquid crystals to express images onscreen), but they use a different type of backlight than what is normally used. Most monitors of the last few years have used cold cathode florescent (CCFL) tubes as their backlight of choice.
Today, more monitor vendors are fully embracing LED backlight technology, with Viewsonic recently announcing that it's shifting its entire monitor line to use LED backlights.
To understand LED backlights, you must understand the three types currently being used in modern computer monitors.
Types of LED backlights
First up are edge-lit backlights using white LEDs (WLED) or EL-WLED. This is the type of LED backlight most commonly used in today's monitors. This entails white LEDs aligned along the edge(s) of the monitor matrix, right behind the liquid crystal array.
Using a special diffuser, the light is spread to cover the entire screen. Monitor vendors have recently refined the technology so that only one edge (not four) need be outfitted with LED lights.
The EL-WLED solution is the cheapest and smallest of the three technologies, which is why it's the most widely used. The advantages of its small design can be seen in displays like the superthin AOC e2243Fw and Samsung PX2370. You'll also see these used in many notebook and Netbook screens, and recently HDTVs have begun adopting the technology as well.
Our next technology is RGB LED. Instead of using white LEDs on one edge of the screen like the previous technology, RGB LEDs are aligned all over the panel matrix.
Each individual light is capable of producing red-, green-, or blue-colored light. This gives the display access to a high color gamut with colors more accurate than what's capable on EL-WLEDs.
Unfortunately, you won't see this technology in use everywhere, as it's very expensive and doesn't allow for a thin design. The $3,500 HP DreamColor LP2490zx uses RGB LED backlights, and its panel measures about 2.25 inches, compared with the $300 Samsung PX2370's 0.6-inch panel depth.
The final type is WLED on a flat array, covering the entire screen. Think of it like an RGB LED that's only using white LEDs instead of tricolor ones. Currently, it's only used in LED-backlit HDTVs; CNET's own David Katzmaier writes about it in depth here.
This brings us to the real question you should be asking: what advantages do LED backlights provide over CCFL backlight solutions? Well obviously this depends on the type of LED backlight; for our purposes, we'll discuss the two used in modern LED-based computer monitors: EL-WLEDs and RGB LEDs.
The following are the most frequently touted advantages of LED-based monitors. Let's get to the bottom of them.
LED backlit monitors have high color gamuts and provide more accurate colors.
Color gamut is controlled by the monitor's color filters and the backlight's radiation spectrum. While CCFL-based monitors typically offer between 72 and 102 percent of the NTSC color space , RGB LED can cover up to 114 percent. EL-WLED does not offer high color gamuts and typically hit around 68 percent of the NTSC color space.
When it comes to color accuracy, before the backlight can be a factor in the precision of a monitor's colors, the display itself must first be capable of producing a high color bit depth. While the color gamut refers to the range of colors a monitor is capable of producing, bit depth determines how many steps of those colors are within that range. The HP DreamColor LP2480zx for example has a 10-bit panel, which allows it to theoretically produce 1.07 billion different colors. Most monitors are limited to 6-bit panels, allowing only 262,000 colors, but through a few technical tricks can "fake" up to 16.2 million colors.
The use of RGB LEDs for backlighting can provide a color spectrum that closely follows the color filtering in the LCD pixel itself. This method allows the color component to be very precise with the color it's using. Also, each individual RGB LED can be tailored to produce the most vivid colors. EL-WLED backlighting is not capable of influencing color in this way.
LED backlit monitors are always superthin.
Only if they're using EL-WLED backlights, as most LED-based monitors do. It's a trade-off between cost and performance. RGB LED provides incredible color performance, but is expensive and bulky. EL-WLEDs don't really influence performance, but can produce monitors less than an inch thick.
LED backlights have lower power consumption.
Yes! At least EL-WLED backlights do. Well, for the most part. The biggest factors that affect monitor power consumption are screen size and luminance. Check out our most recent monitor power consumption chart. Most of the LED-based monitors (all using EL-WLED) are rated as "Good."
LED backlights take less of a toll on the environment when it's time to dispose of them.
True. CCFL technology makes liberal use of mercury, and thanks to the element's high toxicity level, can be a danger to the environment. LEDs contain no mercury and can be recycled much easier.
For most consumers (buying EL-WLED), LED-based monitors will offer low-power-consuming thin panels that are much easier disposed of than CCFL-based displays. Beyond that, unless you're willing to shell out $3,500, that's all you get. Not to shake a stick at power consumption or the environmental impact your purchases have, but you should know where you stand when browsing through the monitor aisle at Best Buy.
The real question is: when will vendors began offering more than just TN-based LED monitors in great numbers? Both BenQ and NEC have made some announcements in this regard this year. Keep an eye on the monitor hub for more coverage on this.
Monitor technology
Panel technology
CRTs have effectively been replaced by their thinner and brighter sister, the LCD. Under the umbrella of LCD technology, there are a few choices to consider before buying a monitor. First, you'll have to decide which panel technology is right for you.
The three main panel technologies currently used in LCDs are: twisted nematic (TN), vertical alignment (VA), and in-plane switching (IPS). In 2011 we saw the debut of a new panel tech from Samsung called Plane to Line-Switching (PLS), which theSamsung SyncMaster S27A850D houses. Manufacturers make the vast majority of consumer monitors using TN panels.
Not surprising, TN panels are the cheapest of the three technologies to make. With a few exceptions, monitors that cost $300 or less will likely have TN panels. The main advantages of TN panels are their fast--usually 2ms--response time and, of course, low price. Their major disadvantages are narrow viewing angles, relatively low brightness, and inaccurate color reproduction.
Next up are VA (mostly known as S-PVA) panels. VAs have improved viewing angles compared with TNs, better color reproduction, and they typically have a much higher maximum brightness. Also, they tend to have the lowest black levels of all four panel technologies. Unfortunately, a VA panel's response time and input lag are not quite as fast as a TN panel, and they can cost anywhere from $400 to $800, and sometimes more depending on the panel's size. Also, you can expect a VA-based monitor's profile to be wider than a TN's.
IPS-based monitors are usually the most expensive; however, the new e-IPS panels cost as little as $300 when incorporated into a 22-inch monitor. They also tie with PLS for the best viewing angles of all the technologies and produce the most accurate colors; however, their blacks are not as deep as VA panels'. IPS monitors are the slowest of the bunch in both response time and input lag.
PLS is a new panel technology from Samsung that debuted with the Samsung Galaxy Tab 10.1 tablet, but the first monitor to make use of the tech was the Samsung SyncMaster S27A850D. PLS panels sport viewing angles as wide as IPS, while offering a higher brightness at a lower cost to power consumption. According to Samsung, production costs for PLS panels are 15 percent lower than that of IPS as well.
Backlight
Let's clear this up right away: LED and LCD technologies are not mutually exclusive. To ask what their differences are is like asking what the difference is between Vibram Five Finger shoes and rubber soles.
So let's break down what LCDs and LED backlights are, as they relate to monitors, and delve into the real advantages of LED backlighting technology.
The term LCD stands for liquid crystal display. LCDs are an upgrade (in most respects) from tube-based CRTs (cathode ray tube) from years of old, although some still prefer CRTs over LCDs. In short, LCDs use liquid crystals to express what you see on the screen. The crystals act as a shutter for the backlight, and, depending on the type of charge given to them by the monitor's built-in electrodes, the crystals will either allow light through to the user or shut it out, thereby allowing the pixels to express their appropriate colors, making up what you see on the screen.
LED-based monitors are still LCDs (they still use liquid crystals to express images onscreen), but they use a different type of backlight than what is normally used. Most monitors of the last few years have used cold cathode florescent (CCFL) tubes as their backlight of choice.
Today, more monitor vendors are fully embracing LED backlight technology, with Viewsonic recently announcing that it's shifting its entire monitor line to use LED backlights.
To understand LED backlights, you must understand the three types currently being used in modern computer monitors.
Types of LED backlights
First up are edge-lit backlights using white LEDs (WLED) or EL-WLED. This is the type of LED backlight most commonly used in today's monitors. This entails white LEDs aligned along the edge(s) of the monitor matrix, right behind the liquid crystal array.
Using a special diffuser, the light is spread to cover the entire screen. Monitor vendors have recently refined the technology so that only one edge (not four) need be outfitted with LED lights.
The EL-WLED solution is the cheapest and smallest of the three technologies, which is why it's the most widely used. The advantages of its small design can be seen in displays like the superthin AOC e2243Fw and Samsung PX2370. You'll also see these used in many notebook and Netbook screens, and recently HDTVs have begun adopting the technology as well.
Our next technology is RGB LED. Instead of using white LEDs on one edge of the screen like the previous technology, RGB LEDs are aligned all over the panel matrix.
Each individual light is capable of producing red-, green-, or blue-colored light. This gives the display access to a high color gamut with colors more accurate than what's capable on EL-WLEDs.
Unfortunately, you won't see this technology in use everywhere, as it's very expensive and doesn't allow for a thin design. The $3,500 HP DreamColor LP2490zx uses RGB LED backlights, and its panel measures about 2.25 inches, compared with the $300 Samsung PX2370's 0.6-inch panel depth.
The final type is WLED on a flat array, covering the entire screen. Think of it like an RGB LED that's only using white LEDs instead of tricolor ones. Currently, it's only used in LED-backlit HDTVs; CNET's own David Katzmaier writes about it in depth here.
This brings us to the real question you should be asking: what advantages do LED backlights provide over CCFL backlight solutions? Well obviously this depends on the type of LED backlight; for our purposes, we'll discuss the two used in modern LED-based computer monitors: EL-WLEDs and RGB LEDs.
The following are the most frequently touted advantages of LED-based monitors. Let's get to the bottom of them.
LED backlit monitors have high color gamuts and provide more accurate colors.
Color gamut is controlled by the monitor's color filters and the backlight's radiation spectrum. While CCFL-based monitors typically offer between 72 and 102 percent of the NTSC color space , RGB LED can cover up to 114 percent. EL-WLED does not offer high color gamuts and typically hit around 68 percent of the NTSC color space.
When it comes to color accuracy, before the backlight can be a factor in the precision of a monitor's colors, the display itself must first be capable of producing a high color bit depth. While the color gamut refers to the range of colors a monitor is capable of producing, bit depth determines how many steps of those colors are within that range. The HP DreamColor LP2480zx for example has a 10-bit panel, which allows it to theoretically produce 1.07 billion different colors. Most monitors are limited to 6-bit panels, allowing only 262,000 colors, but through a few technical tricks can "fake" up to 16.2 million colors.
The use of RGB LEDs for backlighting can provide a color spectrum that closely follows the color filtering in the LCD pixel itself. This method allows the color component to be very precise with the color it's using. Also, each individual RGB LED can be tailored to produce the most vivid colors. EL-WLED backlighting is not capable of influencing color in this way.
LED backlit monitors are always superthin.
Only if they're using EL-WLED backlights, as most LED-based monitors do. It's a trade-off between cost and performance. RGB LED provides incredible color performance, but is expensive and bulky. EL-WLEDs don't really influence performance, but can produce monitors less than an inch thick.
LED backlights have lower power consumption.
Yes! At least EL-WLED backlights do. Well, for the most part. The biggest factors that affect monitor power consumption are screen size and luminance. Check out our most recent monitor power consumption chart. Most of the LED-based monitors (all using EL-WLED) are rated as "Good."
LED backlights take less of a toll on the environment when it's time to dispose of them.
True. CCFL technology makes liberal use of mercury, and thanks to the element's high toxicity level, can be a danger to the environment. LEDs contain no mercury and can be recycled much easier.
For most consumers (buying EL-WLED), LED-based monitors will offer low-power-consuming thin panels that are much easier disposed of than CCFL-based displays. Beyond that, unless you're willing to shell out $3,500, that's all you get. Not to shake a stick at power consumption or the environmental impact your purchases have, but you should know where you stand when browsing through the monitor aisle at Best Buy.
The real question is: when will vendors began offering more than just TN-based LED monitors in great numbers? Both BenQ and NEC have made some announcements in this regard this year. Keep an eye on the monitor hub for more coverage on this.
CRTs have effectively been replaced by their thinner and brighter sister, the LCD. Under the umbrella of LCD technology, there are a few choices to consider before buying a monitor. First, you'll have to decide which panel technology is right for you.
The three main panel technologies currently used in LCDs are: twisted nematic (TN), vertical alignment (VA), and in-plane switching (IPS). In 2011 we saw the debut of a new panel tech from Samsung called Plane to Line-Switching (PLS), which theSamsung SyncMaster S27A850D houses. Manufacturers make the vast majority of consumer monitors using TN panels.
Not surprising, TN panels are the cheapest of the three technologies to make. With a few exceptions, monitors that cost $300 or less will likely have TN panels. The main advantages of TN panels are their fast--usually 2ms--response time and, of course, low price. Their major disadvantages are narrow viewing angles, relatively low brightness, and inaccurate color reproduction.
Next up are VA (mostly known as S-PVA) panels. VAs have improved viewing angles compared with TNs, better color reproduction, and they typically have a much higher maximum brightness. Also, they tend to have the lowest black levels of all four panel technologies. Unfortunately, a VA panel's response time and input lag are not quite as fast as a TN panel, and they can cost anywhere from $400 to $800, and sometimes more depending on the panel's size. Also, you can expect a VA-based monitor's profile to be wider than a TN's.
IPS-based monitors are usually the most expensive; however, the new e-IPS panels cost as little as $300 when incorporated into a 22-inch monitor. They also tie with PLS for the best viewing angles of all the technologies and produce the most accurate colors; however, their blacks are not as deep as VA panels'. IPS monitors are the slowest of the bunch in both response time and input lag.
PLS is a new panel technology from Samsung that debuted with the Samsung Galaxy Tab 10.1 tablet, but the first monitor to make use of the tech was the Samsung SyncMaster S27A850D. PLS panels sport viewing angles as wide as IPS, while offering a higher brightness at a lower cost to power consumption. According to Samsung, production costs for PLS panels are 15 percent lower than that of IPS as well.
Backlight
Let's clear this up right away: LED and LCD technologies are not mutually exclusive. To ask what their differences are is like asking what the difference is between Vibram Five Finger shoes and rubber soles.
So let's break down what LCDs and LED backlights are, as they relate to monitors, and delve into the real advantages of LED backlighting technology.
The term LCD stands for liquid crystal display. LCDs are an upgrade (in most respects) from tube-based CRTs (cathode ray tube) from years of old, although some still prefer CRTs over LCDs. In short, LCDs use liquid crystals to express what you see on the screen. The crystals act as a shutter for the backlight, and, depending on the type of charge given to them by the monitor's built-in electrodes, the crystals will either allow light through to the user or shut it out, thereby allowing the pixels to express their appropriate colors, making up what you see on the screen.
LED-based monitors are still LCDs (they still use liquid crystals to express images onscreen), but they use a different type of backlight than what is normally used. Most monitors of the last few years have used cold cathode florescent (CCFL) tubes as their backlight of choice.
Today, more monitor vendors are fully embracing LED backlight technology, with Viewsonic recently announcing that it's shifting its entire monitor line to use LED backlights.
To understand LED backlights, you must understand the three types currently being used in modern computer monitors.
Types of LED backlights
First up are edge-lit backlights using white LEDs (WLED) or EL-WLED. This is the type of LED backlight most commonly used in today's monitors. This entails white LEDs aligned along the edge(s) of the monitor matrix, right behind the liquid crystal array.
Using a special diffuser, the light is spread to cover the entire screen. Monitor vendors have recently refined the technology so that only one edge (not four) need be outfitted with LED lights.
The EL-WLED solution is the cheapest and smallest of the three technologies, which is why it's the most widely used. The advantages of its small design can be seen in displays like the superthin AOC e2243Fw and Samsung PX2370. You'll also see these used in many notebook and Netbook screens, and recently HDTVs have begun adopting the technology as well.
Our next technology is RGB LED. Instead of using white LEDs on one edge of the screen like the previous technology, RGB LEDs are aligned all over the panel matrix.
Each individual light is capable of producing red-, green-, or blue-colored light. This gives the display access to a high color gamut with colors more accurate than what's capable on EL-WLEDs.
Unfortunately, you won't see this technology in use everywhere, as it's very expensive and doesn't allow for a thin design. The $3,500 HP DreamColor LP2490zx uses RGB LED backlights, and its panel measures about 2.25 inches, compared with the $300 Samsung PX2370's 0.6-inch panel depth.
The final type is WLED on a flat array, covering the entire screen. Think of it like an RGB LED that's only using white LEDs instead of tricolor ones. Currently, it's only used in LED-backlit HDTVs; CNET's own David Katzmaier writes about it in depth here.
This brings us to the real question you should be asking: what advantages do LED backlights provide over CCFL backlight solutions? Well obviously this depends on the type of LED backlight; for our purposes, we'll discuss the two used in modern LED-based computer monitors: EL-WLEDs and RGB LEDs.
The following are the most frequently touted advantages of LED-based monitors. Let's get to the bottom of them.
LED backlit monitors have high color gamuts and provide more accurate colors.
Color gamut is controlled by the monitor's color filters and the backlight's radiation spectrum. While CCFL-based monitors typically offer between 72 and 102 percent of the NTSC color space , RGB LED can cover up to 114 percent. EL-WLED does not offer high color gamuts and typically hit around 68 percent of the NTSC color space.
When it comes to color accuracy, before the backlight can be a factor in the precision of a monitor's colors, the display itself must first be capable of producing a high color bit depth. While the color gamut refers to the range of colors a monitor is capable of producing, bit depth determines how many steps of those colors are within that range. The HP DreamColor LP2480zx for example has a 10-bit panel, which allows it to theoretically produce 1.07 billion different colors. Most monitors are limited to 6-bit panels, allowing only 262,000 colors, but through a few technical tricks can "fake" up to 16.2 million colors.
The use of RGB LEDs for backlighting can provide a color spectrum that closely follows the color filtering in the LCD pixel itself. This method allows the color component to be very precise with the color it's using. Also, each individual RGB LED can be tailored to produce the most vivid colors. EL-WLED backlighting is not capable of influencing color in this way.
LED backlit monitors are always superthin.
Only if they're using EL-WLED backlights, as most LED-based monitors do. It's a trade-off between cost and performance. RGB LED provides incredible color performance, but is expensive and bulky. EL-WLEDs don't really influence performance, but can produce monitors less than an inch thick.
LED backlights have lower power consumption.
Yes! At least EL-WLED backlights do. Well, for the most part. The biggest factors that affect monitor power consumption are screen size and luminance. Check out our most recent monitor power consumption chart. Most of the LED-based monitors (all using EL-WLED) are rated as "Good."
LED backlights take less of a toll on the environment when it's time to dispose of them.
True. CCFL technology makes liberal use of mercury, and thanks to the element's high toxicity level, can be a danger to the environment. LEDs contain no mercury and can be recycled much easier.
For most consumers (buying EL-WLED), LED-based monitors will offer low-power-consuming thin panels that are much easier disposed of than CCFL-based displays. Beyond that, unless you're willing to shell out $3,500, that's all you get. Not to shake a stick at power consumption or the environmental impact your purchases have, but you should know where you stand when browsing through the monitor aisle at Best Buy.
The real question is: when will vendors began offering more than just TN-based LED monitors in great numbers? Both BenQ and NEC have made some announcements in this regard this year. Keep an eye on the monitor hub for more coverage on this.
LCD monitor basics
Now that we've covered panel and backlight technologies, other specifications and features should factor into your buying decision. Here are the most important ones. Be warned, the vendor will not quote all of these specifications and you may have to rely on reviews--like the ones at CNET--to get the details on them.
Not every monitor ships with every video cable it can use, so if you find yourself in need, we recommend hitting up
Movies shot in 2.35:1 (like "Iron Man") are always letterboxed, whether on 16:9 or 16:10 monitors, unless you zoom the image.
Essentially, a 16:9 monitor can display a full-screen 16:9 Blu-ray or digital movie shot in 1.85:1 without stretching the image to fit the screen. A 16:10 monitor will need to stretch the same movie's image a bit to get it to full screen without any black bars.
Black Level: No display can show black without some light seeping through. Black level is a measurement of how much light emanates from the display while showing black.
Brightness: A measurement of how much light a panel can produce. Luminance is expressed in candelas per square meter (cd/m2). A measurement of 200 to 250 cd/m2) is OK for most productivity tasks; 300 to 400 cd/m2 is great for movies and games.
Contrast ratio: The difference in light intensity between the brightest white and the deepest black.
Though contrast ratios typically don't exceed 1,000:1 on monitors, lately, manufactures have been pushing dynamic contrast as a spec, and sometimes misleadingly calling it contrast ratio.
Before a monitor is released to the public, panels go through testing in the vendor's own lab. These tests produce the specs that the vendor will then publish with the release of the monitor. Specs such as maximum brightness, pixel pitch, pixel response time, contrast ratio, and dynamic contrast ratio are all determined in the vendor's lab.
When testing normal contrast ratio, vendors use a device that measures luminance to determine how much light is emanating from a display while it's showing both a completely black and a completely white screen. They then take each number, do a bit of math, and come up with the contrast ratio.
Now, aside from a relatively low number of LCDs that use LED-backlighting technology, all LCDs have a lamp built into their screens. When you turn your brightness setting down, you're actually just dimming the lamp in the back. When the vendors dim the backlight to get the contrast ratio score, they dim it to a point, but do not turn it off.
When they test to get the readings for dynamic contrast, however, they turn off the backlight.
With the backlight off, the darkness of the black level increases by a factor of 10 or more. At this point, the vendor takes its reading for the dark screen and compares it with the white screen reading it recorded earlier. Since this new dark screen level is so dark, it increases the contrast ratio. The problem is that the screen only gets this dark when the video signal is black or near black--not very useful when you're watching a movie, or playing a game, or doing pretty much anything. The primary reason for including this feature is that the contrast ratio goes from 1,000:1 to 10,000:1, and even 30,000:1.
When vendors push dynamic contrast as a spec for LCDs that use LED-backlighting technology, however, it may be more appropriate. Direct contrast ratio works differently with LEDs than with lamp-based LCDs. When a portion of an image in a movie is relatively dark, the LEDs in that local area of the screen are dimmed. This occurs on a frame-by-frame basis and lowers the black level in that dark area only. Unfortunately, this implementation has its weaknesses, as well, as there can be some noticeable visual glitches in the areas that darken.
Bottom line? Take all measured specs with a grain of salt; however, take dynamic contrast specs with a huge bucketload of salt.
DisplayPort: Heralded as the successor to DVI and HDMI, DisplayPort is a higher-bandwidth connection that could facilitate thinner and lighter monitors as they would no longer require special circuitry (and hardware to run that circuitry) to receive video signal. While we saw an increased adoption of DisplayPort among mobile PCs and graphics cards in 2011, the monitor segment is still only slowly ramping up support for the technology, thanks to comparatively low profit margins and the industry's reliance on legacy ports like VGA.
DVI: Some newer monitors forgo including digital visual interface (DVI) in favor of HDMI. If this is the case with the monitor you're interested in, make sure the monitor includes a DVI-to-HDMI cable or that your video card supports an HDMI connection. Having said that, we recommend getting a monitor with at least one DVI connection.
HDMI: An HDMI connection is used to connect the display to a high-definition source, such as a Blu-ray player, video game system, or a DVR-based HD cable/satellite set-top box. HDMI connections have become more common recently and it's the exception now when a monitor, 22 inches and larger, doesn't have one. If you're planning to use your monitor as a television, this is an essential feature.
Pixel-response rate: This refers to how quickly a pixel can change colors, measured in milliseconds (ms); the lower the milliseconds, the faster the pixels can change, thus reducing the ghosting or streaking effect you might see in a moving or changing image. Based on new evidence, however, it's likely you won't see any streaking or ghosting in a modern LCD when watching a movie.
Input lag: A delay in which the LCD's image lags behind what's been sent to the screen. Not everyone notices input lag, and vendors rarely, if ever, quote this figure for their monitors. Input lag affects gamers the most. If split-second reactions are paramount in your gaming sessions, do some research as to a monitor's input lag before you buy.
Ergonomic options: Most LCDs offer some degree of screen tilt, usually 30 degrees back and 5 degrees forward. Some include a swivel feature, many offer height adjustability, and some panels can also pivot between portrait and landscape modes, making legal-size documents and Web pages easier to view. Some LCDs can be attached to VESA-compatible mounts that connect to third-party wall mounts or swinging arms.
Resolution: Dictated by screen size, aspect ratio, and sometimes the manufacture's digression. Make sure you are comfortable with an LCD's native resolution before you buy it. Remember, an LCD that scales its image to a non-native resolution will never look as good.
Memory card readers: A few monitors have media card readers built into the bezels. This is a handy addition for digital photo enthusiasts who want to see their pictures without using a PC.
USB: Many displays have USB ports. Typically, they are not powered hubs, but simply convenient ports to connect low-powered devices such as a keyboard or a mouse, thereby reducing the tangle of cables that run back to the computer.
Audio: Some monitors offer audio functions, either as standard items or as optional accessories. These may include a headset jack, a volume control, or embedded speakers. In general, these speakers are of limited quality, and an inexpensive $30 speaker set from an office-supply or computer store will often provide much better sound.
Viewing angle: Largely dictated by panel technology. 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 manufacturers' specifications with a grain of salt and make your own observations, if possible.
HDTV: As work and entertainment products continue to converge, many monitors now have features designed to take advantage of television and movie content. Some include TV tuners and connectors for video signals from cable television systems or antennas. Many new monitors are simply HDTVs in disguise.
Not every monitor ships with every video cable it can use, so if you find yourself in need, we recommend hitting up
Movies shot in 2.35:1 (like "Iron Man") are always letterboxed, whether on 16:9 or 16:10 monitors, unless you zoom the image.
Essentially, a 16:9 monitor can display a full-screen 16:9 Blu-ray or digital movie shot in 1.85:1 without stretching the image to fit the screen. A 16:10 monitor will need to stretch the same movie's image a bit to get it to full screen without any black bars.
Black Level: No display can show black without some light seeping through. Black level is a measurement of how much light emanates from the display while showing black.
Brightness: A measurement of how much light a panel can produce. Luminance is expressed in candelas per square meter (cd/m2). A measurement of 200 to 250 cd/m2) is OK for most productivity tasks; 300 to 400 cd/m2 is great for movies and games.
Contrast ratio: The difference in light intensity between the brightest white and the deepest black.
Though contrast ratios typically don't exceed 1,000:1 on monitors, lately, manufactures have been pushing dynamic contrast as a spec, and sometimes misleadingly calling it contrast ratio.
Before a monitor is released to the public, panels go through testing in the vendor's own lab. These tests produce the specs that the vendor will then publish with the release of the monitor. Specs such as maximum brightness, pixel pitch, pixel response time, contrast ratio, and dynamic contrast ratio are all determined in the vendor's lab.
When testing normal contrast ratio, vendors use a device that measures luminance to determine how much light is emanating from a display while it's showing both a completely black and a completely white screen. They then take each number, do a bit of math, and come up with the contrast ratio.
Now, aside from a relatively low number of LCDs that use LED-backlighting technology, all LCDs have a lamp built into their screens. When you turn your brightness setting down, you're actually just dimming the lamp in the back. When the vendors dim the backlight to get the contrast ratio score, they dim it to a point, but do not turn it off.
When they test to get the readings for dynamic contrast, however, they turn off the backlight.
With the backlight off, the darkness of the black level increases by a factor of 10 or more. At this point, the vendor takes its reading for the dark screen and compares it with the white screen reading it recorded earlier. Since this new dark screen level is so dark, it increases the contrast ratio. The problem is that the screen only gets this dark when the video signal is black or near black--not very useful when you're watching a movie, or playing a game, or doing pretty much anything. The primary reason for including this feature is that the contrast ratio goes from 1,000:1 to 10,000:1, and even 30,000:1.
When vendors push dynamic contrast as a spec for LCDs that use LED-backlighting technology, however, it may be more appropriate. Direct contrast ratio works differently with LEDs than with lamp-based LCDs. When a portion of an image in a movie is relatively dark, the LEDs in that local area of the screen are dimmed. This occurs on a frame-by-frame basis and lowers the black level in that dark area only. Unfortunately, this implementation has its weaknesses, as well, as there can be some noticeable visual glitches in the areas that darken.
Bottom line? Take all measured specs with a grain of salt; however, take dynamic contrast specs with a huge bucketload of salt.
DisplayPort: Heralded as the successor to DVI and HDMI, DisplayPort is a higher-bandwidth connection that could facilitate thinner and lighter monitors as they would no longer require special circuitry (and hardware to run that circuitry) to receive video signal. While we saw an increased adoption of DisplayPort among mobile PCs and graphics cards in 2011, the monitor segment is still only slowly ramping up support for the technology, thanks to comparatively low profit margins and the industry's reliance on legacy ports like VGA.
DVI: Some newer monitors forgo including digital visual interface (DVI) in favor of HDMI. If this is the case with the monitor you're interested in, make sure the monitor includes a DVI-to-HDMI cable or that your video card supports an HDMI connection. Having said that, we recommend getting a monitor with at least one DVI connection.
HDMI: An HDMI connection is used to connect the display to a high-definition source, such as a Blu-ray player, video game system, or a DVR-based HD cable/satellite set-top box. HDMI connections have become more common recently and it's the exception now when a monitor, 22 inches and larger, doesn't have one. If you're planning to use your monitor as a television, this is an essential feature.
Pixel-response rate: This refers to how quickly a pixel can change colors, measured in milliseconds (ms); the lower the milliseconds, the faster the pixels can change, thus reducing the ghosting or streaking effect you might see in a moving or changing image. Based on new evidence, however, it's likely you won't see any streaking or ghosting in a modern LCD when watching a movie.
Input lag: A delay in which the LCD's image lags behind what's been sent to the screen. Not everyone notices input lag, and vendors rarely, if ever, quote this figure for their monitors. Input lag affects gamers the most. If split-second reactions are paramount in your gaming sessions, do some research as to a monitor's input lag before you buy.
Ergonomic options: Most LCDs offer some degree of screen tilt, usually 30 degrees back and 5 degrees forward. Some include a swivel feature, many offer height adjustability, and some panels can also pivot between portrait and landscape modes, making legal-size documents and Web pages easier to view. Some LCDs can be attached to VESA-compatible mounts that connect to third-party wall mounts or swinging arms.
Resolution: Dictated by screen size, aspect ratio, and sometimes the manufacture's digression. Make sure you are comfortable with an LCD's native resolution before you buy it. Remember, an LCD that scales its image to a non-native resolution will never look as good.
Memory card readers: A few monitors have media card readers built into the bezels. This is a handy addition for digital photo enthusiasts who want to see their pictures without using a PC.
USB: Many displays have USB ports. Typically, they are not powered hubs, but simply convenient ports to connect low-powered devices such as a keyboard or a mouse, thereby reducing the tangle of cables that run back to the computer.
Audio: Some monitors offer audio functions, either as standard items or as optional accessories. These may include a headset jack, a volume control, or embedded speakers. In general, these speakers are of limited quality, and an inexpensive $30 speaker set from an office-supply or computer store will often provide much better sound.
Viewing angle: Largely dictated by panel technology. 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 manufacturers' specifications with a grain of salt and make your own observations, if possible.
HDTV: As work and entertainment products continue to converge, many monitors now have features designed to take advantage of television and movie content. Some include TV tuners and connectors for video signals from cable television systems or antennas. Many new monitors are simply HDTVs in disguise.
Image quality
What to look for:
Office work/Web surfing
A few tips on how to look for what you want.
Viewing angle: Look at the monitor from different angles and be aware of how much the colors shift or if the screen darkens. Also, pay attention to the angle when the screen begins to look different. Colors and brightness should not change when viewing the screen from an off angle, either from the sides, top, or below. TN panels will be the most egregious offender.
Text: Go to a Web site and scrutinize the legibility of small text. Firefox lets you change the font size from its options menu. Also, be aware of any color-tint problems when viewing black text on a white background
Accurate colors: View something you're familiar with, like a digital photo of a loved one or colleague you see every day, on the monitor; notice how different the colors in the picture look on the monitor.
Glossy screens can seemingly increase the contrast of movies and games. Some don't appreciate the extreme reflectiveness, however. View both glossy and matte screens, and decide which looks better to you.
Low black level: The closer a monitor can get to displaying black, the better. True black is illusive and the most you can hope for is that a monitor displays very dark gray. Check out dark scenes in movies, and notice how dark the black gets without actually losing the detail of a scene.
An adequate graphics card is a necessity
What's going on inside your computer can have a profound effect on what's displayed on your monitor. If you hook up a 4- or 5-year-old PC to a top-of-the-line new monitor, there's a good chance your graphics card will need an upgrade to give you the best possible image quality. You'll need a card that supports your interface, be it DVI or HDMI, and it will need to support your monitor's resolution--this is especially important on 30-inch models with 2,560x1,600-pixel resolutions. Sometimes, improving your graphics card's performance can be as easy as installing a driver upgrade from the manufacturer's Web site.
Office work/Web surfing
- Good text reproduction
- High brightness
- No ghosting during fast gameplay
- No delay in onscreen action after entering a command
- Low black level
- Wide viewing angle
- Accurate colors
- Accurate colors
- Good viewing angle
A few tips on how to look for what you want.
Viewing angle: Look at the monitor from different angles and be aware of how much the colors shift or if the screen darkens. Also, pay attention to the angle when the screen begins to look different. Colors and brightness should not change when viewing the screen from an off angle, either from the sides, top, or below. TN panels will be the most egregious offender.
Text: Go to a Web site and scrutinize the legibility of small text. Firefox lets you change the font size from its options menu. Also, be aware of any color-tint problems when viewing black text on a white background
Accurate colors: View something you're familiar with, like a digital photo of a loved one or colleague you see every day, on the monitor; notice how different the colors in the picture look on the monitor.
Glossy screens can seemingly increase the contrast of movies and games. Some don't appreciate the extreme reflectiveness, however. View both glossy and matte screens, and decide which looks better to you.
Low black level: The closer a monitor can get to displaying black, the better. True black is illusive and the most you can hope for is that a monitor displays very dark gray. Check out dark scenes in movies, and notice how dark the black gets without actually losing the detail of a scene.
An adequate graphics card is a necessity
What's going on inside your computer can have a profound effect on what's displayed on your monitor. If you hook up a 4- or 5-year-old PC to a top-of-the-line new monitor, there's a good chance your graphics card will need an upgrade to give you the best possible image quality. You'll need a card that supports your interface, be it DVI or HDMI, and it will need to support your monitor's resolution--this is especially important on 30-inch models with 2,560x1,600-pixel resolutions. Sometimes, improving your graphics card's performance can be as easy as installing a driver upgrade from the manufacturer's Web site.
Monitor warranties
When choosing a monitor, consider the company behind it.
First and foremost, make sure that the company offers a money-back guarantee. Most displays will show its problems right out of the box or within the first month or two of use, so you want to be able to return it for a refund or an exchange with a minimum of hassle. A 90-day return policy is standard, but this varies among retailers (many online retailers give you only 30 days). Also, beware of restocking fees.
Next, consider the warranty coverage. Most companies offer two to three years of parts-and-labor coverage; anything less is suspect. Make sure that the backlight is covered by the warranty; manufacturers used to exclude them from coverage, but more and more now include them. Also note a company's policy on defective pixels; one or two defects are to be expected, but if there are many, you should be able to return the unit for exchange or a refund. Some companies deal with pixel problems on a "case-by-case" basis, meaning that they don't have a set policy. If you end up with a problematic display, you'll have to negotiate with the company. This is where the satisfaction-guaranteed return policy can become very important.
You're far less likely to need technical support for a monitor than for a computer system or a software program. Still, it's good to know that there's someone you can call if trouble arises; look for toll-free support numbers and weekend coverage.
Be sure to keep all of the packing material for your monitor. If you should ever need to return it or ship it back for warranty service, you'll need the packaging. Monitors can be bulky, fragile, and extremely difficult to protect adequately. You don't want to end up improvising when shipping it.
To find out more about how warranties really stack up and what you should look for in a vendor's service and support, look at Computer Guru's hardware warranty explainer.
User reviews
Although CNET's monitor reviews attempt to completely cover all facets of a monitor a user would be concerned about before purchasing, we can't cover everything. In particular, thanks to the nature of product loan agreements usually required to get new products in, we cannot accurately predict how a monitor will perform a year after purchase. This is where user reviews truly show their value. The impressions of a user a year after owning a monitor may be very different from CNET's evaluation after only a few weeks.
First and foremost, make sure that the company offers a money-back guarantee. Most displays will show its problems right out of the box or within the first month or two of use, so you want to be able to return it for a refund or an exchange with a minimum of hassle. A 90-day return policy is standard, but this varies among retailers (many online retailers give you only 30 days). Also, beware of restocking fees.
Next, consider the warranty coverage. Most companies offer two to three years of parts-and-labor coverage; anything less is suspect. Make sure that the backlight is covered by the warranty; manufacturers used to exclude them from coverage, but more and more now include them. Also note a company's policy on defective pixels; one or two defects are to be expected, but if there are many, you should be able to return the unit for exchange or a refund. Some companies deal with pixel problems on a "case-by-case" basis, meaning that they don't have a set policy. If you end up with a problematic display, you'll have to negotiate with the company. This is where the satisfaction-guaranteed return policy can become very important.
You're far less likely to need technical support for a monitor than for a computer system or a software program. Still, it's good to know that there's someone you can call if trouble arises; look for toll-free support numbers and weekend coverage.
Be sure to keep all of the packing material for your monitor. If you should ever need to return it or ship it back for warranty service, you'll need the packaging. Monitors can be bulky, fragile, and extremely difficult to protect adequately. You don't want to end up improvising when shipping it.
To find out more about how warranties really stack up and what you should look for in a vendor's service and support, look at Computer Guru's hardware warranty explainer.
User reviews
Although CNET's monitor reviews attempt to completely cover all facets of a monitor a user would be concerned about before purchasing, we can't cover everything. In particular, thanks to the nature of product loan agreements usually required to get new products in, we cannot accurately predict how a monitor will perform a year after purchase. This is where user reviews truly show their value. The impressions of a user a year after owning a monitor may be very different from CNET's evaluation after only a few weeks.
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