Crystal Clear

By Team Digit Published Date
01 - May - 2005
| Last Updated
01 - May - 2005
Crystal Clear
LCD monitors have been on the verge of mass usage for a long time now. But the fact that sales never took off despite them catching the fancy of computer users bears ample testimony to the fact that there are still some issues with the products that need to be sorted out-primarily, cost and value for money.

The good news is that prices have been dropping steadily over the past few months, to the point that many of us-even home users-can easily think of owning one. Nineteen-inch LCDs, unlike their CRT counterparts, remai beyond the reach of most of us, so we tested 15-inch and 17-inch LCD monitors-to be precise, 15 models from 15 brands in the 15-inch category, and 11 models from 10 brands in the 17-inch category.

Remember that unlike with CRTs, you don't get an inch or two chopped off the viewable area-if it says 15 inches, almost all of it is viewable.

LCDs have suffered in the past in terms of acceptance because of their mediocre performance in the movies and games department, and also because of the  restricted viewing angle. With better manufacturing processes, not only have prices come down, performance, too, in many areas has improved.

Apart from the fact that the technology is entirely different, LCD monitors differ in many non-intuitive ways from CRTs. For example, LCDs have a 'native resolution' at which they work best.

In LCD monitors, the pixels are hard-etched on the panel, and so cannot display crisp images at any resolution other than the native resolution

Remember, LCDs aren't the ideal solution for everyone out there-read on to find out whether to go the LCD way. We compared several LCDs based on aesthetic and technical aspects, as well as price-so you can make a sound decision on which one to buy.

Key Features
Here are some features to look at before you decide upon a model. Although our list is not exhaustive, it represents the most important things you need to know about and look out for.

Some things, such as the pixel pitch, are different from the CRT equivalent. Also, contrast ratios and such have different typical values in LCDs than CRTs.

Pixel Pitch
The pixel pitch is the distance between two white pixels, or two sub-pixels of the same colour. (A white pixel is made up of three sub-pixels-one red, one green and one blue.) The monitors we received in both the 15 and 17-inch categories had pixel pitches of 0.297 mm and 0.264 mm respectively-this is almost a universal standard. The individual size of each sub-pixel is, of course, smaller than the pixel pitch.

Native Resolution
In LCDs, the pixels are hard-etched on the panel, and therefore cannot display crisp images at any resolution other than the native resolution-unlike CRT monitors. The 15-inch and 17-inch models we received had native resolutions of 1024 x 768 and 1280 x 1024 pixels respectively-this, too, is almost universal.

If you change the resolution setting, you will see a badly focused image, and hard-to-read fonts with blurred edges.

Luminance and contrast ratio are of prime importance in LCDs. The luminance rating depends on the monitor's fluorescent lamp, built into the casing. The brighter the lamp, the better. The lamp rating is what determines the brightness level the monitor can achieve.

In the 15-inch category, the CMV CT-529A had the highest luminance rating: 450 cd/m2 (candelas per square metre). This is the vendor-specified rating, and, if correct, it means that the LCD can look bright even in a fully-lit room.

The Acer AL1512 claims a luminance rating of 350 cd/m2, which is higher compared to the rest of the bunch which maxed out at 250 cd/m2. The Philips 150s had the lowest luminance rating of 200 cd/m2, which means you need to make sure light doesn't hit the screen directly.

In the 17-inch monitor category again, the CMV CT-712A had a 400 cd/m2 luminance rating, followed by the ViewSonic and the Acer at 380 cd/m2 and 370 cd/m2 respectively. The CMV's better lamp makes it easy for the user to tweak the brightness of the monitor according to the ambient light.

Contrast Ratio
The contrast ratio is the ratio of the brightness of pure white versus pitch black that the monitor displays. A higher contrast ratio means the user can set the monitor to display images with better visual depth. Also, a monitor with a higher contrast ratio helps the user fine-tune the panel to suit different lighting conditions.

Although LCD monitors do come with an 'Auto' setting feature that takes care of the brightness, contrast and geometry, this feature is usually not perfect, and the user almost always has to do some tweaking. A contrast ratio of 120:1 is enough to display most colours. However, an even higher contrast ratio allows the panel to display more greyscales. This means you'll be able to see more shades of colour on an LCD with a higher contrast ratio.

Among the 15-inchers, the CMV and the HCL claimed the highest contrast ratio of 500:1, which is impressive, and which means the user has a wide range of contrast and brightness to play with, from pitch black to really bright. The Philips 150s has a poor contrast ratio of 250:1, leaving little room for tweaking.

In the 17-inch models, the highest contrast ratio-550:1-was logged by the LG Flatron L1730S. It was followed by the BenQ and CMV at 500:1.
Tighter physical dimensions are always talked about when LCDs are compared with CRTs.

In the 15-inch category, the S-Media and BenQ boasted depths of just 12.8 and 13.6 cm respectively. This takes into account the base as well, and not just the panel. The ViewSonic VE510b had the smallest width and height of just 32.5 cm and 32.3 cm-it was a really neat package.

In the 17-inch category, the LG Flatron L1730S was sleek-it was just 11.5 cm deep, making it stand out from the rest. The NEC left enough space, width- and height-wise, to place it on a table under the file shelf and place stereo speakers on either side.

A higher contrast ratio means the user can set the monitor to display images with better visual depth

The Winsonic L17X, a new entrant in the LCD monitor segment, on the other hand, was comparatively very large-42.5 cm tall and 20.4 cm thick.

Monitors are not peripherals that see often changes in physical placement-weight, therefore, doesn't really matter that much. But of course, you'd always prefer a lighter monitor!

How We Tested 
The monitors were tested keeping in mind performance, features, and value for money. Before running the tests, the monitors were placed perfectly vertical in order to eliminate any uniformity issues, and were auto-calibrated. All monitors were set to their native resolutions, and their drivers were loaded so we could get them to perform at their best.

The Test Bed Configuration: Both-the reference and test systems-were running on a P4 3.0 GHz CPU with 1 GB of DDR SDRAM, an nVidia 5950 Ultra graphics card, and a 7200 rpm SATA hard drive.

Features: In the Features tests, we looked for value-additions and other aspects that aimed at increasing the user-friendliness of the display. The features noted varied in significance-some were simple, like the user-friendliness of the OSD (On Screen Display); some were  important, like power consumption, depth and weight.
One important thing we looked at was the monitor base, which decides the tilt the monitor is capable of-the more the better.
Some LCDs can be rotated vertically-landscape to portrait. This is useful while reading a long Word file or a PDF without the aid of a scroll-wheel mouse.
An oft-overlooked feature is the supplied user manual and quick start guide. It is especially helpful if the manual clearly states the full technical specifications of the monitor.

Performance: We used the DisplayMate benchmarking software to gauge the LCD monitor's performance. This software uses images to test a monitor for criteria such as Point Shape and Visibility. For example, to gauge how accurately the LCD can display a fine point, and whether or not it is able to retain the round shape of the dot, can be guaged by this test.
In the colour and greyscale set of tests, we checked for colour reproduction, the level shift problem, and the streaking or ghosting effect. We ran the 16-intensities and 64-level primary and secondary colour intensities tests to see how well the monitors could display shades.
In the miscellaneous tests within DisplayMate, we checked for screen uniformity. We also tested the Reverse Video Contrast.
The Pixel Persistence Test was run to check for jerks or image blurring. We used the Passmark Monitor Test to check for image persistence at the edges.
 For the viewable angle test, we used a protractor placed inline with the LCD panel, and the screen was viewed from either side. A document containing different fonts was viewed from various angles, letting us determine the angles at which the text still looked sharp.

Price: We took the price of each monitor vis-Ã -vis its features and performance into account.

How we awarded
The features, performance and price scores were given relevant weightages, and an overall score out of 100 was calculated. The product that scored the highest was adjudged the winner of the Digit Best Buy Gold award for its category, while the second highest got the Digit Best Buy Silver award.

Of the 15-inch monitors, the CMV CT-529A was the lightest at just 2.6 kg, followed by the S-Media at 2.7 kg. The Philips 150s, at 5 kg, was the heaviest.

In the 17-inch segment, the CMV CT-712A was the lightest at 3.4 kg, followed by the Acer at 3.49 kg. The NEC LCD1770NXM is the heaviest, at 6.5 kg-which is very heavy by LCD standards.
If a monitor allows for height adjustment, you can set it to the level that makes for most comfortable viewing. And monitors that do not allow for height adjustment will require you to adjust the height of your chair, which is not a good thing. In the 15-inch category, not a single monitor had this useful feature. It wasn't much better in the 17-inch category, either-just three panels, the HCL, the NEC and the Philips, had the height adjustment feature. You can adjust the height of these monitors by about 11 cm.

Horizontal and vertical swivel is another good feature found in a few LCD monitors. Most monitors allow for vertical tilt, but very few allow for horizontal swivel. In the 15-inch segment, the Digiview was the only monitor that had both horizontal and vertical swivel. The rest came with the provision only for vertical tilt. Amongst the 17-inchers, again, just two brands-HCL and NEC-offered horizontal as well as vertical tilt.

Other Features
These days, some graphics cards, including even some entry-level ones, come with the DVI interface.

If the monitor has a DVI input, there is no signal conversion happening in the monitor, so the overall image quality is much better than with the D-sub interface. Sadly, none of the monitors in the 15-inch category had a separate DVI interface to accept a pure-digital signal from a graphics card.

This means that even if you have a graphics card that can deliver a pure-digital signal, you will be forced to feed it to the monitor through the D-sub connector. In the 17-inchers,the BenQ, NEC and Philips had DVI inputs.

Power Consumption
A salesman selling an LCD monitor will never forget to mention the power consumption rating of LCD monitors vis-Ã -vis CRT monitors. It is a fact that LCD panels consume less power compared to CRT monitors, but it is also true that the power requirements are often not substantially lower.

Fifteen-inch LCDs need anything between 21W and 35W. Seventeen-inchers need between 40W to 60W of power, which, compared to the 64W needed by the Philips 107E5 CRT monitor, is just a small improvement.

Always remember to check the power rating of the LCD you are thinking of investing in, and note whether there is substantial power saving possible. Of course, for a home user, this doesn't make too much difference-it's in an office, where several monitors are deployed, that power costs add up to make a difference.

How They Fared
The monitors were tested using DisplayMate Video Edition and the Passmark monitor test utility, along with several real-world tests-these included the viewing angle test and looking for the ghosting effect during movies.

Sharpness And Resolution
We checked for the sharpness of the image using the Point Shape and Visibility screen in DisplayMate, consisting of a fine white dot. We looked for pixel bleeding, and found that most monitors had some amount of bleeding at the edge. This bleeding results in a red, green or blue tinge at the edge of the dot. Only the ViewSonic VE510b (15-inch) and VA712 (17-inch) returned acceptable results.

In the video bandwidth test, a fine white line is drawn on a black background. This screen is used to see how accurately the lines are drawn and whether there are any discrepancies.

In the 15-inch category, the AOpen and S-Media displayed blue tinges running across the length of the line at the edge, whereas the Winsonic L1562S, due to its high brightness, made the black background look like a shade of grey. In the 17-inch category, except for the Philips, all monitors returned a crisp line.

This test is important for those who use imaging software, where accurate reproduction of finer elements is important.

Download the PDF File of LCD Monitors

The ghosting, or streaking, effect is a major problem with LCD monitors. Ghosting is basically the presence of light or dark shadows that trail an image in areas where large changes in intensity are present. It is visible when images on the screen move at a speed faster than the pixels' response time. This puts undue strain on the eyes.

To check for ghosting, we ran four different ghosting screens in DisplayMate, and found that most monitors returned good results, the exception being the 15-inch AOpen F1513, which displayed streaking in the Colour Streaking screen.

In this test, the monitors managed such good results because they didn't have to deal with moving images. We therefore ran an additional test that involved watching a movie clip that showed fast-moving objects.

In the 15-inch category, we found the BenQ FP537s giving the best results, with very little ghosting visible. In the 17-inch category, it was again the BenQ-the FP731-which came out on top.
Level Shift
Here, we looked for the white and black level shifts, which happen when two adjacent areas differ greatly in contrast. In this test, most 15-inch displays fared well with very little level shift visible, except for the AOpen F1513, where the white level shift was evident.

Of the 17-inch monitors, the BenQ FP783 did suffer from level shift, but not to the extent that it could cause eye strain.

Level shift, if high, can be a big problem in Photoshop-like applications, where there are often light and dark areas adjacent to each other.

Text-Colour Combination
In this test, we checked for a monitors reproduced coloured fonts on backgrounds of different colours.

LCDs have red, green and blue sub-pixels that make up a pixel. When coloured text, say magenta, is displayed on a grey background, you can easily identify the black space between two magenta dots, making the font look serrated.

Of the 15-inchers, the Umax returned impressive overall results-it had no problems with magenta fonts. The CMV CT-529A and the Winsonic L1562S, on the other hand, returned poor results: both yellow and magenta fonts appeared like a collection of dots.

In the 17-inch category, it was again the CMV CT-712A that returned lower-than-average results. The rest of the 17-inchers fared pretty well too.

Intensity Levels
In this set of tests, we looked for how well the LCD monitors could display 16, 64 and 256 shades of grey (these are the ranges that the benchmark suites provide for).

The 64-Intensities test with secondary colours, and the 256-Intensities tests, are rather difficult for LCD monitors-hardly any monitor can display more than 64 shades correctly. In this, contrast and brightness play an important role, as an overly bright screen will not display shades of grey in the light region, and a dark screen will merge shades on the darker side.

All the 15-inch monitors fared well in the 16-Intensities and 64-Intensities tests for primary colours, except for a couple: the Winsonic L1562S and the LG L1530S merged a few levels on the brighter and darker sides respectively. In the 256-Intensities test, the PureView PV 15C displayed thick black and white bands (meaning that it merged the shades) on either side of the spectrum. This can be a problem, especially while watching movies, where dark scenes will appear overly dark, hence snuffing out the details.

The Winsonic L17X, in the 17-inch category, scored low compared to the others in this test. This means that the user will need to manually calibrate the monitor for contrast and brightness rather than relying on the auto setting.

Miscellaneous Tests

Screen Uniformity And Reverse Video Contrast
In this test, coloured text on white and two different shades of grey was used. In the 15-inch category, the S-Media was the only monitor that suffered in screen uniformity: it displayed several shades of grey. The reverse video contrast test was easy for all the 15-inchers; they all passed it without much variation in quality.

Among the 17-inch monitors, the Winsonic, HCL and NEC scored lowest: there was clearly-visible variation throughout, in the screen uniformity test. The Philips 170s returned solid results, with a very consistent screen, corner-to-corner. The reverse video contrast test did not pose problems for any of the 17-inch monitors.
Passmark Monitor Test
We used the LCD pixel persistence test in the Passmark monitor test to check for the pixel persistence problem with the panels. In this test, a bright white block moves at various speeds across the monitor, ranging from 100 pixels/second to 800 pixels/second.

The entire set of monitors in both categories failed to display even the slowest moving block without persistence-all of them scored very low.
Our test results lead us to believe that none of the LCDs we tested are at a stage where they could be considered good for games or movies. If you're into gaming, you're better off with a CRT. If you want to watch movies on an LCD panel, don't expect an exceptional viewing experience.

Viewable Angle Test
Here, we used a text screen in DisplayMate, and a movie scene, to find the maximum viewing angle of each monitor. In the 15-inch category, the HCL HCM 510LSA had the smallest viewing angle in text and movie mode-137 and 122 degrees respectively.

Most panels returned a higher viewing angle in text mode-this was because of the bright background. They suffered in the movie test because the movie was a mix of bright outdoors and dimly-lit indoors scenes. The ViewSonic VE510b reached 140 degrees in the movie, which was highest we saw in the 15-inch category.

In the 17-inch segment, the Philips 170s managed only 127 degrees in the text test, whereas the CMV, HCL and LG returned 132 degrees in the movie test. The BenQ FP783 and the Philips 170S managed 148 degrees, which was the highest we saw.

The Acer AL1512 carries a price tag of Rs 9,999 excluding taxes, whereas the 17-inch Acer is available for as low as Rs 14,999, which makes it cheaper than some of the 15-inch models. There are still brands such as NEC, which sell at a premium-Rs 22,500 for the 15-inch model, which is about Rs 5,000 more than other well-known brands such as Philips, ViewSonic and BenQ.

And The Winner Is…
If you take into consideration just pure performance, the 15-inch BenQ FP537s comes out tops. A worthy mention where performance is concerned is the ViewSonic VE510b. But neither of these monitors could make it to the top because of their price tags.

Price played an important role in deciding our Gold winner, which is the Acer AL1512. It fared comparatively well in both performance and features, but its really low price-just Rs 9,999-helped it edge pass models that performed equally well. The CMV CT-529A, which is our Silver winner, returned features and performance scores similar to the Acer, but is slightly higher priced.

In the 17-inch category again, price played a major role in deciding our winner, and the Acer AL1714sm, with a price tag of just Rs 14,999, won Gold.

Most of the other monitors had similar features and performance scores, but are priced very differently. The Acer, which is the cheapest 17-inch model, retails for just Rs 14,999. This makes it cheaper than many 15-inch models, whereas the NEC 1770NXM is priced at a whopping Rs 39,500. The kind of performance that the NEC 1770NXM and the BenQ FP783 gave was similar to that of less expensive models from other brands, and at the same time, they did not carry features that could justify the high prices.

The Silver winner in the 17-inch category is the CMV CT-712A, which is very competitively priced at Rs 17,000.

To Buy Or Not To Buy…
LCDs have their pluses and their minuses. We've mentioned the main pluses. And they have their cons too-movies and games are CRT territory.

One reason LCDs are not suitable for games is that they're fixed resolution-so you end up either playing your game in a small window, or with all the action blurred. The fixed resolution can be a problem in other areas as well. As for movies, it depends. Some of us really will not find fault with the way movies look on an LCD; some of us will.

Whether to go in for an LCD monitor is something to think about for a while. LCDs look good, have flaunt value, and the image, in general, is crisper than that on a CRT. For popularity to grow, however, costs have to come down, the nitty-gritties that persist have to fade away and the user needs to know that this makes the best sense-for business or pleasure. So, are you ready to go slim?

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