LED (Light Emitting Diode) backlighting is now becoming so widely adopted in consumer LCD monitors that it’s almost surprising to see a monitor without it. Some attractive ‘environmental’ benefits of replacing CCFL (Cold Cathode Fluorescent Lamp) backlighting with LEDs include lower power consumption at a given brightness, less heat produced and a mercury-free end product. LED backlighting also makes the monitor thinner and lighter which is good if you need to shift it from room to room or building to building. Some manufacturers even make claims of image quality improvements such as enhanced brightness, ‘purer’ whites and a flicker-free experience.
Thankfully we have reviewed and tested our fair share of LED-backlit computer monitors so when we heard about the Dell ST2320L our excitement wasn’t marred by any kind of false expectation. As you have probably guessed by now the Dell ST2320L is another monitor which features LED backlighting using strips of white LEDs around the inside of the bezel (edge-lit LED) in place of CCFL lamps. We look at and beyond this ‘feature’ as we test the Dell ST2320L and analyse its performance in games, movies and other applications.
The specifications of the ST2320L are much as you would expect from a modern LED-backlit monitor. According to the specifications the ST2320L is a lightweight and energy efficient monitor with ‘all round’ specifications. The typical RRP of the monitor is also quite a comfortable sub-£200 setting the Dell up at an attractive pricepoint.
A quick glance at the Dell ST2320L reveals a face that lacks the finesse of Samsung’s ‘premium’ LED-backlit range. It has a fairly typical gently curved glossy black look that is perhaps a little overdone on modern monitors. There is a silver ‘lip’ at the bottom that prevents the ST2320 looking entirely ordinary – but this looks like it could have been thrown into the design at the last minute and is not as elegant as Samsung’s seamless Perspex additions. The stand is similarly humdrum; a glossy circle that doesn’t afford any height or swivel adjustment to the monitor. Nonetheless – the tilting mechanism is nice and smooth and requites little resistance to tilt the monitor.
Only so much can be said about a monitor from the side. The ST2320 is again glossy and black and reasonably thin; but at 20mm the new Samsung and BenQ LED-backlit range are slightly more svelte.
Some of the depth of the monitor, however, is simply to house the inputs and power converter at the rear of the monitor. The inputs are down-facing and include connection ports for a wide range of peripherals – DVI-D, HDMI, D-sub (VGA), audio in, audio out and an AC input (power). Interestingly Dell only includes a VGA cable with the monitor and it’s already plugged in – perhaps this is a statement that the ST2320L can handle the signal just fine with no noticeable quality degradation. We found the image to look pretty much the same either way, but we did use our humble DVI cable as we just prefer things to be all digital where possible.
The rear of the monitor is also a glossy black affair with a small amount of matte black plastic beneath the inputs, the stand neck and rear third of the stand.
Once the ST2320L is connected and powered up an icy white light illuminates the centre of the silver lip, just beneath the Dell logo.
The image on the screen, using default settings, also has a wintery look about it – it appears to be too ‘cool’ in tone and actually quite washed out. It will need some tweaking which can be done using software and of course the humble OSD (on-screen display). The OSD is controlled by touch-sensitive areas towards the bottom of the right bezel edge. There is a lack of illumination here and no tactile feedback, so adjustment in the dark is pretty tricky.
The OSD menu is small and simple and allows basic adjustments such as selecting an image preset or altering brightness and contrast. The image presets include; Standard, Multimedia, Game, Warm, Cool, and Custom (RGB). The latter mode allows the levels of red, blue and green to be independently altered. You can also select ‘menu’ to enter a more advanced setup mode that allows you to access further settings such as various picture adjustments and the ability to perform an ‘LCD Conditioning’. This cycles through screenfills of red, green, blue, black and white and is designed to ease ‘mild image retention’.
We performed a simple calibration of the ST2320L using the ‘Display Color Calibration’ feature of Windows 7. Whilst the use of a colorimeter would have led to better results, we felt it was more appropriate and fair to use a by-eye calibration procedure that is readily accessible to home users – the ST2320L is not a ‘professional’ panel and shouldn’t be treated as such. The LED backlighting of the ST2320L means that it is not necessary to wait 30 minutes or more for the screen to ‘warm up’ prior to calibrating – but we still do so out of habit. It is important to bear in mind that that the ST2320L is a Twisted Nematic (TN) panel so the gamma curve of the monitor is highly viewing angle dependent. This makes it impossible to calibrate the entire monitor screen and you are only really calibrating specific points of the monitor from a particular viewing angle – doing this by eye requires that you are sat in your ‘usual’ position.
We observed a reasonably high level of ‘bleaching’ at the default brightness and contrast settings. Instead of using the Windows 7 calibration images (which rely on a distinction between black and white); we observed familiar desktop backgrounds and a set of icons and adjusted the settings via the OSD to try and reduce the washed out appearance. No amount of adjustment gave particularly pleasing results – in the end we stuck with ‘82’ brightness and ‘50’ contrast. This was still a significant improvement over the default setting though so progress nonetheless. The exact nature of the problem became readily apparent when we adjusted the gamma slider in the Windows 7 calibration tool – it was far, far too high on the ST2320L by default. By lowering the gamma slider to about 1/3 of the way from the bottom and using our already revised contrast and brightness settings the bleaching was significantly reduced. This was no magic wand though – the overall image now appeared fairly dull, particularly towards the top of the screen. Despite this whites were still overly intense and there were elements of bleaching – but we didn’t dwell on this too much as games and movies tend to ignore the ICC/ICM profiles that calibration procedures set up anyway.
Dell claims the usual 250 cd/m2 typical luminance and 1000:1 static contrast ratio which we have no reason to doubt – but nonetheless we will assess these claims using our testing methods. Not one to be left behind on the insane and frankly ludicrous figures game, Dell states a phenomenal 8m:1 dynamic contrast ratio. When dynamic contrast is enabled the backlight intensity is varied depending on the level of black and white (dark and light) on the screen. This means that the backlight would be turned off (or very close to it) if an entirely black screen was to be displayed whereas the backlight would turn onto maximum brightness in an entirely white scene. The resulting “dynamic” contrast ratio is therefore very high but only using a setting that is impractical for most applications.
To put Dell’s claims to the test we measured the luminance of an entirely white image, an entirely black image and the resulting contrast ratio using various settings. The table below shows these results with significant results highlighted in blue and discussed in the proceeding section. Unless otherwise stated assume a contrast level of 100%.
|Monitor profile||White luminance (cd/m2)||Black luminance (cd/m2)||Contrast ratio (x:1)|
|Standard, 100% brightness
|Standard, 80% brightness
|Standard, 60% brightness||242||0.92||263|
|Standard, 40% brightness
|Standard, 20% brightness
|Standard, 0% brightness
|Standard (ICC profile used), 82% brightness, 50% contrast
|Standard (ICC profile not used), 82% brightness, 50% contrast||132||0.96||138|
|Multimedia, 82% brightness
|Game, 82% brightness
|Warm, 82% brightness
|Cool, 82% brightness
From the table above, you can see that Dell’s stated 1000:1 static contrast ratio was unachievable using any settings. The closest we came was at 100% brightness, achieving a rather meagre 307:1 contrast ratio. The image itself was appalling at this setting. Blacks looked purple due partly to fairly significant backlight bleedthrough issues at both the top and bottom of the monitor. The bottom right corner in particular suffered from a ‘spotlighting’ effect due to the bleedthrough. When considering ‘normal images’ the very bad gamma issues that we discussed previously meant that the whole screen looked completely bleached using this setting with excessive amounts of white throughout. Although the white luminance was only recorded as 319 cd/m2; the sheer amount of it on the screen and relative intensity makes the screen very difficult to look at. The stated typical luminance of 250 cd/m2 is quite believable at this setting but there’s nothing typical about the blinding mess you see on the screen.
Under standard settings achieving anything resembling deep black involved lowering the brightness right down to 0%. At this setting blacks looked reasonably deep in the screenfill although minor excess backlight bleed-through could still be seen at the bottom edge of the monitor. Despite the low white luminance value of 117 the sheer extent of the bleaching and excessive amount of white on the screen made the monitor difficult to look at. The ST2320L was obviously never supposed to run at 100% contrast – even the surprisingly low contrast ratios are artificially inflated by this’ unrealistic’ setting and the 1000:1 stated static contrast ratio is a distant dream. By applying our ICC profile and adjusting contrast and brightness levels accordingly the screen was bearable to look at but the luminance and contrast ratio suffered; we recorded quite shocking sub-200:1 values.
Much to our dismay (read: pleasure) the dynamic contrast function didn’t seem to work at all. We enabled game mode and made sure the setting was switched on in the same way as on other Dell UltraSharp monitors we’ve reviewed and then presented the ST2320L with a black screen. The backlight didn’t seem to dim at all. A Dynamic Contrast ratio of 297:1 doesn’t sound quite as appealing as the stated 8m:1 does it?
Moving past these rather shoddy figures and onto the real testing now. First off we tested Battlefield: Bad Company 2 and found that the glare and explosions in the game were nice and bright with pure whites to be found throughout. We mean that a little too literally, however, as unfortunately the poor gamma of the screen leaves much of the image looking bleached. We played around with various OSD settings and in-game settings but to no avail. On game levels where glare is particularly prevalent (that’s most of them) the game is uncomfortable to play and things become very hard to distinguish. Not that it matters in the grand scheme of things but dark areas also looked excessively light on the game and to a large degree this killed the ‘dark’ atmosphere of some maps. We do give due praise to the intense and pre looking whites of snow, though, which greatly added to the atmosphere and that feeling of snow-blindness.
In Operation Flashpoint: Dragon Rising explosions, glare from the sun and bright reflections all seemed nice and bright with pure white throughout. Glare features a lot less extensively on Dragon Rising than on Bad Company 2 so the image didn’t appear as heavily bleached but was still washed out. Reducing in-game gamma simply added a dull element to the already drained look. There was minor loss of detail in dark areas (particularly on the character uniforms) but in the main the problem was quite the opposite; most things in the dark were simply too visible. Night on the game looked plain wrong – no need for nightvision here. On the final game title we tested, Colin McRae: Dirt 2, the bleached and watch out effect returned with a vengeance and a pair of sunglasses wouldn’t have gone amiss. Whites were again impressively bright and pure; it’s just a shame about the rest of the image.
We aren’t film critics but we will be a little critical about the ST2320L’s contrast performance on the Blu-ray movie titles we tested. The Girl with the Dragon Tattoo appeared, perhaps unsurprisingly, quite bleached. This really destroyed the atmosphere in dark scenes and these were a major part of the film. To see if we could examine the problems using slightly more technical tests we used a series of LCD tests provided by Lagom. These tests are designed to bring any weaknesses in a monitors performance to the user’s attention; even if they would not normally be clear.
Performance on the contrast test was decent but not outstanding. All bars were fairly indistinct at the top end although they could still be distinguished if you looked closely enough. The bottom three blue bars were indistinguishable from each other and the background but the low end for other colours was ok.
The black level test results were decent but clearly influenced by vertical viewing angle. From directly in front of the monitor all but the first 4 blocks were distinguishable from the background. By moving your head downwards or scrolling upwards so only the first half of boxes were visible on the screen the first 4 blocks were also distinguishable from the background. Also noticeable was some temporal and static dithering that affected some of the lighter squares.
The white saturation test results were fairly poor. Things would have undoubtedly been much worse if the ICC profile was not applied, but even considering that it was applied the final four checkerboard patterns were invisible and the fifth-last was difficult to distinguish. Given the ‘bleaching’ of the monitor these results were hardly surprising.
The greyscale gradient was ok but showed distinct banding at the lower third and small amounts of temporal dithering – but nothing majorly wrong.
The ST2320L provided fairly lacklustre colour performance on the game titles we tested. Due in no small part to the poor gamma of the ST2320L the image on Bad Company 2 was heavily bleached and colours appeared quite literally washed out. There were some patches of slightly more lush and vibrant greens but they were few and far between. Dragon Rising appeared similarly washed out but there was not even a spot of vibrant or otherwise impressive colour anywhere on this game. Even the skin of the characters hand managed to look wrong. We were similarly unenthused by the performance on Dirt 2 where the car paint jobs lacked their usual vivid and ostentatious colours. The Malaysian forests looked slightly less washed out than the overall image elsewhere but this was predominantly due to the rather unsightly yellow-tinted greens.
Our Blu-ray movie titles gave similarly disappointing results. The Girl with the Dragon Tattoo had very drab colours throughout with very pale skin tones that made all of the characters look ill. To try to achieve the opposite effect we fired up the typically vivacious Futurama: Into the Wild Green Yonder. We were sorely disappointed – the colours lacked the vibrancy we’ve come to expect from this title. Colours that were supposed to be neon appeared slightly pastel whereas pastel colours and deep colours both looked equally and overly washed out.
To investigate the effects of viewing angle on colour reproduction we also ran the viewing angle tests of Lagom. The ST2320L performed much as you would expect from a TN panel on these tests (if not slightly worse). The purple block appeared pink at the left side, particularly in the bottom left corner and also towards the bottom right. The red block appeared pink at the bottom and only mustered a bleached red towards the very top – the pinkness shifted alongside head movement. The green block appeared a garish lime green throughout with a slightly accented yellow note at the bottom. As we usually find with the blue block it appeared a relatively uniform blue – but it wasn’t as deep as we would have liked and was noticeably deeper blue in the top left corner. The Lagom ‘text test’, which is a quick way of identifying the viewing angle dependency of a monitors gamma curve, didn’t surprise us and confirmed that the gamma curve of the ST2320L is highly viewing-angle dependent – appearing red tinted for the most part and green tinted towards the top. For normal desktop monitor usage (i.e. sat in front with the monitor fairly central to your field of vision) the experience in games, movies and on the desktop is not hampered by the imperfect viewing angle performance of the ST2320L so much as the overall lacklustre colour quality from which there is no escaping.
So the image quality of the ST2320L we tested wasn’t so hot. What about the responsiveness? Surely it can gain some ground here? Unfortunately our experiences on games tell us otherwise. On both Bad Company 2 and Dragon Rising the responsiveness wasn’t particularly impressive. There was noticeable trailing that was omnipresent when driving about or strafing (even quite slowly in the case of Dragon Rising) that really detracted from the experience. On Dirt 2 we noticed excessive trailing that was, of course, coupled with excessive bleaching. This made it very difficult to play as the track and other cars on the track would blur and things became too difficult to focus on. On our movie titles things were a little better but still substandard. On Futurama the bold colours moving against one another often exacerbate any problems with a panel’s responsiveness and with trailing evident throughout the ST2320L was no exception. Things were a little better on The Girl with the Dragon Tattoo; trailing appeared fairly minor and not particularly distracting. During fast movement scenes the trailing did become more evident but this is often the case on any monitor – we really prefer games as a more rounded test of responsiveness as you actually interact with them and they aren’t limited by the frame rates at which the film action is shot.
If you’ve come straight to this section without reading the rest of the review then prepare to become rapidly disillusioned with the Dell ST2320L – just like we were as we tested it. The monitor itself is a fairly plain looking black glossy affair with some nice little touches like touch sensitive buttons and an ice-white power light that illuminates the silver bottom lip. Once the monitor is switched on, however, any externalities will soon be forgotten. The ST2320L has a huge problem with excessively high gamma. This creates a ‘bleached’ image that leads to overpowering whites and lacklustre colours that are particularly ominous in the game titles we tested. Whilst it is possible to reduce the gamma using in-game settings and on the desktop using custom ICC profiles (i.e. calibration) this actually leads to a dull looking image with unacceptably low luminance (indistinct colours), poor contrast and still elements of bleaching. Given the rather palpable issues we were having with the screen – such as the gamma issues and the fact that dynamic contrast simply didn’t do anything it is possible that the individual screen that we were reviewing was faulty in some way – from our experience, though, this is less than likely. One thing that you can certainly not escape from and will be almost invariable on any ST2320L unit is the substandard responsiveness. We wouldn’t feel foolish saying that Dell’s UltraSharp IPS monitors (yes – those ones people traditionally frown upon due to a figure on paper that says ‘6’ or ‘8’ instead of ‘2’ or ‘5’) are far more responsive than the ST2320L. But one cannot ignore the price of the monitor – at under £160 it is certainly one of the cheaper LED-backlit monitors currently available. One can speculate all they like about the ‘what if’s of this particular panel vs. other panels of the same model and possibly subsequent revisions; but based on what we have tested we cannot recommend the ST2320L.
|Bright and brilliant whites throughout
||Major gamma problems mean that the image appears bleached with excessive white
|Dynamic contrast mode doesn’t seem to work
||Dynamic contrast mode doesn’t seem to work
|Touch-sensitive buttons are ‘cool’ and ‘totally now’
||Touch sensitive buttons are a pain to use in the dark seeing as they aren’t illuminated on the ST2320L. Grubby fingerprints also affect that glossy area|
|The monitor displays different colours
||The monitor displays washed-out colours that haven’t heard of the word ‘vibrant’ and are poor even for a TN panel
|One of the cheapest monitors of the size to provide LED-backlighting for better energy efficiency and a thinner profile
||There are some comparatively priced (or cheaper) monitors at the time of review that offer superior image quality|