BenQ EW2420

The majority of new ‘home user’ computer monitors released recently have given us a severe case of Déjà vu. The image quality has shown slight variation in default colour temperature and maximum brightness; but the underlying panel technology has been largely similar. Things were shaken up a bit with the release of Dell’s new U2211H and U2311H UltraSharp monitors. These fell in the mid-high end of the ‘home user’ price bracket but offered an alternative type of technology previously reserved for the professional user market; IPS (In-plane switching). IPS technology affords a monitor markedly superior colour reproduction and viewing angles to the usual TN (Twisted Nematic) panel technology at a slight cost in responsiveness.

BenQ has not only shaken things up a bit, but have also caused a bit of a storm with the release of their latest LED-backlit monitors – the VA and EW series. You can’t take any cues from the price or aesthetics because they fit so perfectly with what has been released previously. What goes on under the bonnet, however, is very different indeed. Like the UltraSharps, these monitors stray from the norm by offering a novel panel type – in this case, *VA (Vertical Alignment). They are also the world’s first monitors to combine a VA panel with an LED backlight. The use of a *VA panel suggests that the EW2420 we review herein will provide enhanced colour reproduction, better viewing angles and superior contrast to other monitors in that price range. It all seems a bit too good to be true – if the price difference is immaterial, what is the real cost of this technology? That’s what we intend to find out.


The BenQ EW2420′s specifications reveal some interesting attributes that might just seperate the monitor from the crowd (highlighted in light blue). The first thing to note is that the panel type is AMVA with an impressively high stated static contrast ratio of 3000:1. The viewing angles are also a little higher than the usual 170 horizontal and 160 vertical degrees stated by BenQ for their TN panels whilst the 8-bit per pixel colour support (without dithering) is favourable to the usual 6-bits per pixel. The response time, on the other hand, is a comparatively high 8ms G2G. This is also one of the first monitors to combine a VA panel with an LED backlight which is good progress from BenQ. It should be noted that the power consumption is slightly higher than a similarly sized LED-backlit TN panel due to the VA panel. The maximum power consumption stated includes the USB ports being active and the backlight set to maximum brightness – in practice expect power consumption of sub-30W. In this EW2420 review we test a range of applications to see how the specifcations are reflected in the real-world performance of the monitor.

Screen size: 24 inches
Panel type: AU Optronics M240HW02 V1 Vertical Alignment (AMVA) LCD
Native resolution: 1920 x 1080
Colour support: 16.7 million (8-bits per pixel without dithering)
Response time (G2G): 8ms
Refresh rate: 60Hz
Weight: 6.1kg
Contrast ratio: 3,000:1 (20m:1 Dynamic Contrast)
Viewing angle: 178º horizontal, 178º vertical
Maximum power consumption:40W (28W typical using our settings)
Backlight: W-LED (edge-lit)
Typical RRP as reviewed: £170 ($US TBC)




The BenQ EW2420 sports an understated and unfussy look. It’s still an attractive looking monitor – unless of course you hate black glossy plastics with hints of dark grey right at the bottom. If you do hate all things gloss then you may seek solace from the matte plastic added to the mix at the rear of the monitor. Here you will also find a plethora of useful inputs; D-Sub (VGA), DVI-D, 2 x HDMI 1.3, 2 x USB downstream, 1 x USB upstream and an AC (power) input. There are an additional two USB downstream ports and a headphone line-in on the left side of the monitor. Despite this excellent connectivity, *VA panel, internal power adaptor and the OSD controls mounted on the right side of the monitor, the EW2420 remains reasonably slender. The OSD controls themselves, which are mounted on the side of the monitor, have a nice tactile feedback to them. Unfortunately there is no illumination on the bezel and no on-screen menu labels to assist in the dark. What’s more infuriating under any ambient lighting conditions is the unintuitive OSD navigation system (with separate ‘menu’ and ‘enter’ button with ‘up’ and ‘down’ buttons sandwiched between them) and the sluggish response of the OSD itself. There is no power button or LED at the front of the monitor, which is a bit unusual and perhaps a little disconcerting – but at least the side-mounted power light isn’t distracting in the dark.

Despite the slender appearance of the EW2420 it actually has a fair bit of weight behind it which makes it feel like a serious bit of kit and not the usual ‘BenQ toy’. The stand itself is a little less than solid (particularly the neck) and you will probably be unsurprised to hear that a slight tilt backwards and even more slight tilt forwards is the limit of the EW2420s adjustability. If this is of particular concern then rejoice as the EW2420 includes the appropriate stand for VESA mounting. Despite the somewhat flimsy stand the monitor doesn’t slide about on the desk if you try to use the controls; a real bonus for a BenQ monitor. Another bonus is the screen of the monitor itself. This has a mild anti-glare coating and could be described as ‘semi-glossy’. Aggressive matte coatings are designed to scatter and absorb ambient light so that reflections aren’t a problem. Unfortunately it’s a two-way system so this also affects the light emitted from the monitor itself. With the semi-glossy coating of the EW2420 you don’t get the usual colour-dulling, grainy ‘sparkle’ effect that more aggressive matte coatings may provide. Direct sunlight or particularly dark scenes on the monitor can cause minor reflections but this is far less of a problem than on true glossy screens.



To calibrate the EW2420 at a fairly basic level we used the Windows 7 ‘Display Color Calibration’ procedure coupled with familiar desktop backgrounds and icons; we are sure better results could be obtained using a colorimeter (highly recommended for professional applications), but we felt it would be fairer and more appropriate to adjust the monitor settings using a method that is readily accessible to home users. Because the EW2420 is LED-backlit it isn’t necessary to wait for 30 or more minutes for the backlight to warm up and the colour temperature to stabilise; but we did so anyway. For further advice about calibrating monitor please read this TFT Central article.

To adjust the contrast and brightness to comfortable levels for our uses we observed familiar desktop backgrounds and icons, as well as the Lagom black level tests and adjusted via the OSD. In the end we settled for ‘68’ brightness and ’58 contrast’. This gave excellent definition and a lovely vibrancy to colours without upsetting more subtle shades. Obviously individual panels will differ as will personal preferences and these values should be adjusted with these things in mind – we also use slightly lower brightness settings when working on the monitor at night.

The colour balance of the monitor was actually very good indeed. This was determined by a comparison of images and the Windows 7 colour-balance adjustment screen between the EW2420 and our high-end reference CRT. The light from an LED backlight is itself slightly blue in colour, especially compared with the warmer ‘yellow’ tone of light emitted from a CCFL backlight. We often find that LED-backlit monitors have a ‘cool’ tone and are therefore too strong at displaying blues relative to greens and reds. Given this the EW2420′s default colours came as a nice surprise. It should be noted that individual panels, different graphics cards and different drivers can lead to very different colour balance. There have been some reports of the expected ‘blue tint’ so you may have to reduce the blue-level slightly. This can easily be remedied using the OSD, which we recommend over a software solution (such as the Windows 7 calibration tool) as the same settings will be applied to games and movies and not just the desktop.

Although not strictly related to calibration, BenQ includes a feature called ‘AMA’ (Advanced Motion Acceleration) on the EW2420 that can be enabled in the OSD. This is an overdrive feature designed to accelerate grey to grey transitions and make motion appear smoother – this does make a difference, so we advise you enable it as we did. This is explained in more detail later in the review.



BenQ claims the EW2420 is capable of producing brightness in the 250cd/m2 range and a static contrast ratio of 3000:1. The latter claim is fairly audacious given that most panels would struggle to come close to the 1000:1 the manufacturers state. Unlike dynamic contrast, whereby the backlight intensity is varied depending on the level of black vs. white on the screen, the backlight would remain on even if a totally black screen was to be displayed. The inevitable bleed through, even if minor, would raise the luminance of the black and therefore decrease the possible contrast ratio. Because the backlight can be turned off to display a black screen and turned on fully for a white screen in a dynamic contrast scenario, you get much higher contrast ratios which allows manufacturers to play the ridiculously high numbers game. BenQ have joined the party with their purported 20m:1 dynamic contrast ratio for the EW2420.

To test these claims we used our esteemed light meter to record some values for the brightness (luminance) of an entirely white image, an entirely black image and the resulting contrast ratio using various settings on the EW2420. The results are shown in the table below with significant values highlighted in blue and discussed in the proceeding section. For ‘Standard’ modes assume a contrast level of 100% unless otherwise stated – other preset modes may vary contrast.

Monitor profile White luminance (cd/m2) Black luminance (cd/m2) Contrast ratio (x:1)
Standard, 100% brightness
0.42 710
Standard, 80% brightness
258 0.30 860
Standard, 60% brightness 221 0.19 1163
Standard, 40% brightness
172 0.13 1323
Standard, 30% brightness
165 0.08 2063
Standard, 20% brightness 138 0.05 2760
Standard, 0% brightness 97 0.03 3233
Standard, 68% brightness, 58% contrast (test settings)
222 0.17 1306
258 0.33 782
248 0.31 800
288 0.36 800
192 0.16 1200
168 0.09 1867
Full dynamic contrast (Photo preset)
259 <0.01 >25900

From the table above, you can see that the peak contrast ratio recorded was a fantastic 3233:1, exceeding the 3000:1 of the specification. Unfortunately the image is a little dim at “0% brightness” even for desktop work to be comfortable. By increasing the brightness to 20% the EW2420 produced blacks that are exceptionally deep with an overall image luminance that is good enough for most desktop work. We recorded a rather excellent contrast ratio 2760:1 using these settings which is very near the 3000:1 stated by BenQ.

It was clear from our observations (although not necessarily reflected by the table) that the EW2420 cannot cope comfortably with the contrast set to 100%. At 60% brightness (100% contrast) or above, for example, blacks appear fairly deep whilst whites are lovely and bright. Unfortunately the overall image is bleached. At 100% brightness blacks did appear slightly purple in the darkness but even at this setting there was no excessive backlight bleed around the edges or indeed elsewhere on the screen. At this setting we recorded the peak luminance value of 298 cd/m2 from the EW2420. This is good but not entirely unexpected given the 250 cd/m2 ‘typical luminance’ stated by BenQ.

Using our favoured test settings (68% brightness, 58% contrast) we were able to achieve deep looking blacks and bright and clean whites, which reflects the respectable contrast ratio of 1306:1. Although this may seem low in comparison to the peak ratio we recorded at 0% brightness we can assure you that the overall image looks infinitely better. It is also a lot higher than what we typically record for monitors in this price range (with sub 500:1 values being common).

We found BenQ’s dynamic contrast mode slow to react, with the screen taking around 6 seconds to properly dim and another 6 seconds to reach ‘full brightness’ for the very large white square used to test luminance. As aforementioned, enabling dynamic contrast typically produces fantastically low black luminance in the black screen fill; in effect artificially raising the contrast ratio and letting manufacturers run wild with their claims. We recorded a value of > 25900, limited by the 0.01 lux resolution of our light meter. This value could be considerably higher as the black luminance was measured as 0.01 lux and no lower. There probably isn’t an instrument sensitive enough to measure a low enough black level to achieve the 25m:1 BenQ claims at the sub-300 cd/m2 peak luminance that the EW2420 can output. A few extra significant figures won’t hurt, will they BenQ? It’s also worth mentioning at this point that the dynamic contrast mode itself can only be implemented in ‘Movie’, ‘Game’ and ‘Photo’ settings. All three of these modes create wildly oversaturated colours, excessive sharpness and result in relatively poor static contrast ratios. It seems that BenQ really needs to sort their presets out.

Now enough with the numbers and onto the real meat – the image quality in the games and movies we tested on the EW2420. As we had hoped, these impressive figures corresponded with an impressive performance on the game titles we tested. A particular problem with previous *VA panels that we have tested is the considerable gamma shift that tends to ‘crush’ dark greys and colours into a pool of blackness (hence often termed ‘black crush’) – no such problems were exhibited by the EW2420. On Battlefield: Bad Company 2 the EW2420 displayed deep blacks with no loss of detail in dark areas. Meanwhile whites were brilliantly pure which brought sparks, explosions and muzzle flashes to life. The white of snow was also outstanding without subtle detail (such as the grainy texture) being lost. Between the whites and the blacks are the very important colours – they were vivid and lively, showing excellent range. Greens in particular showed exceptional variety on this title.

On Operation Flashpoint: Dragon Rising we were impressed by how well the EW2420 handled different smoke types on the game. There was excellent contrast between the dark dirty smoke of burning vehicles and the bright white smoke grenade smoke. As on Bad Company 2 there was no noticeable loss of detail in dark areas and they looked suitably dark with flashes of true brilliance from explosions and other bright emissions. The muted and gritty aesthetic that the game artists intended for Dragon Rising was conveyed well by the EW2420. The lush green forests and sapphire waters of Bad Company 2 had been replaced by the muted khaki colours of steppe grasslands. The range of greens was again impressive with minty greens, dark greens and earthy brown-greens filling adding to the drab greys and browns of the buildings and ground beneath. The natural look was very pleasing and true to the geographical location and biome of the fictional ‘Skira island’.

The EW2420 returned to vibrant form on Colin McRae: Dirt 2. The dusty greens and browns of Utah were handled brilliantly, whilst the exceptional contrast brought about small details such as rock cracks, even in shaded areas, that would usually go unnoticed. Meanwhile the car paint jobs and banners around the track added much-loved vibrancy to the game with some dashing colours. The lush greens of the Malaysian forests had a particularly healthy glow to them as well.

We also tested out some Blu-ray movies on the EW2420 to see if it would satisfy the cravings of our movie fans. The first title we fired up was The Girl with the Dragon Tattoo. This movie has a gritty look with plenty of dark areas and is great for testing the low-end contrast of the EW2420 in particular. There was no noticeable loss of detail in any of these dark areas and in fact impressively minor details could be seen, such as creases in clothing. Even more outstanding was that the dark brown of the main characters irises were (just about) distinguishable from the blacks of her pupils in scenes where most monitors would make no such distinction. Colours on this were very natural looking as you would hope from such a title – very unlike the spectacular display in our next movie title: Futurama – Into the Wild Green Yonder.

Colours here were nice and vibrant with an excellent range of shades – both vivid and pastel. Colour consistency was very good. Skin tones of a particular character, for example, appear the same colour throughout the characters body. This may seem trivial but this is a good indicator of the viewing angle dependency and ability of a monitor to maintain good subtle colour detail throughout the scene. This is something that invariably trips up Twisted Nematic LCD monitors. What particularly impressed us, however, was the fantastic contrast; especially on the star fields. It really did enhance the experience not only by enriching the colours but also by aiding the distinctions between deep blacks and bright whites.








Of course the ‘real world’ experiences of image quality, from an entertainment perspective, were very positive on the EW2420. To explore these distinctions in a slightly more formal way, however, we shall be using various tests provided by a very useful website – Lagom. First up were the tests for contrast, which gave very pleasing results overall:

Colour gradients were generally good with distinctive brightness steps at each level. There was a slight blending together of the two uppermost blocks of blue, red and purple.

Black level tests were impressive – particularly for a VA panel monitor. All but the first two blocks could be distinguished from the background. No dithering was evident and the white block was brilliantly clean and bright. A slight gamma shift was evident according to head movements but this didn’t cause any problems in our applications.

White saturation performance was very impressive – only the very last checkerboard pattern blended into the white background. If we moved slightly to the side of the monitor this too was visible.

The EW2420 displayed a rather beautiful greyscale gradient – the smoothest we’ve seen on a monitor so far. There was some very faint banding at the low end but the transition from deep black to brilliant white was excellent.

Another area of image quality that the Lagom tests are able to analyse quite well is the viewing angle dependency of the monitor’s gamma curve. Like all *VA panels there is a gamma shift when you move your head around the screen but it is only very slight on the EW2420. Nevertheless, this is something to consider for colour-critical applications where an IPS (In-Plane Switching) model may be more suitable. The results were still highly favourable to any TN (Twisted Nematic) in this department. The purple block appeared mainly purple, although there was a slight pink sheen if you moved your head. Similarly, the red block was mainly red with a minor pink tint that could be noticed if you moved your head. The green block appeared impressively solid and green throughout – and not a horrible yellow-green that most monitors display, either. The blue block was also impressively solid-looking, but deep blue this time. The Lagom ‘text test’ confirmed that the gamma curve of the EW2420 is only slightly viewing angle dependent. There was a very minor black tint towards the bottom of the screen that moves if you move your head but the results here are still impressive. The text was mainly a blended grey without green and red flashes within the normal viewing angle range – indicating a viewing angle dependency far more minor than on a TN-panel display.

The video below makes the shift in colour look a lot more extreme than it perceivably is, but really we are trying to highlight the shifts that occur on the EW2420 at ‘extreme viewing angles’ – if you like to hang upside down from the ceiling then pay attention to this one.



Response time is generally considered to be the Achilles heel of a *VA panel monitor such as the BenQ EW2420. Fortunately the EW2420 does feature a response-time compensation mode called AMA (Advanced Motion Acceleration) that we introduced you to earlier. Because responsiveness is very subjective (it will bother some people more than others and generally you become accustomed to it after using the monitor for a short while) we used an excellent tool called PixPerAn PixPerAn (Pixel Performance Analyser). PixPerAn is favoured by professional review websites such as TFT Central – so if you would like to compare the results of our tests to the monitors in their reviews feel free.

The picture above shows the ‘worst case’ pixel response time of the EW2420 (i.e. the fastest ‘tempo’ on PixPerAn) with BenQ’s AMA response time compensation disabled. You can see a distinct secondary trail, a less distinct third trail and even a faint fourth trail behind the image. This is typical of a *VA panel with RTC (response time compensation) disabled.

This picture (above) shows the same ‘worst case’ pixel response of the EW2420, but this time with AMA response time compensation enabled. It does seem to improve the image smoothness considerably (and in practice the improvement is very noticeable) – but you can see from the image that there is still a fairly strong secondary trail. The ‘third’ trail is now much weaker and there is no visible fourth trail. You can see a slight trail infront of the main image both with and without AMA enabled.

We tested a variety of games across different genres to see how noticeable this ‘trailing’ was during gameplay. We must say that over the course of our testing we became far less sensitive to the response time of the EW2420. It seemed that problems only really become problems if you make them so and are actively seeking them out. The first title we tested for responsiveness was Bad Company 2 – given that some of the action in this is fast paced enough to make a 2ms TN panel look sluggish the results from the EW2420 came as no surprise. For the most-part the responsiveness was just fine and the game was perfectly playable. Looking around for trailing whilst zipping around in an ATV was slightly nauseating as textures seemed to ‘vibrate’ and lose sharpness. Fortunately when we stopped looking out for this specifically the visual experience was a lot more pleasant – and the kill to death ratio was certainly not affected in any negative way by the EW2420 experience. Red Alert 3 (the most up to date Command and Conquer title we own) was also given a quick run through to see how the EW2420 handled RTS titles. Blurring occurred when rapidly scrolling, as it does on most LCD monitors; but the game was perfectly playable without any dizzying sensations. Moving on to a different genre and another of our favourite game titles, Dirt 2. This mostly ran very nicely on the EW2420. This could be partly due to the fact that we tend to concentrate more on the road and the driving itself as opposed to looking out for little niggles in response time but the game was as playable as ever.

So why did we say that Dirt 2 ‘mostly’ ran very nicely? Another aspect of response time, which isn’t really captured on the PixPerAn car test or day-time scenes in games is what is often referred to as ‘black ghosting’. This occurs quite commonly on *VA panels when a light object moves across a considerably darker background (or vice-versa) and manifests itself as a dark ‘smoke like’ trail of black, dark grey or sometimes even reddish purple. This was a huge problem for the Samsung F2380, which lacked any sort of response time compensation – but in truth the ‘extreme’ transitions in colours that can cause ‘black ghosting’ are generally not accelerated so much by improvements in ‘grey to grey’ response times. For this reason ‘black ghosting’ was sometimes evident on the EW2420, but certainly to a lesser extent than on the Samsung F2380. This was particularly noticeable on dark missions on Dragon Rising, for example, where moving past dark objects sometimes produced a slight smoke-like trail. Similarly on Dirt 2 the darker tracks seemed to blur a little as we went around them. This wasn’t enough to impede our determined performance though, it has to be said. These were both extreme examples – some games are mainly somewhere between pitch dark night and bright daylight, such as the gritty Resident Evil 5. We ran the rolling benchmark and did get a slight feeling of motion sickness; mainly because we were not in control of the action itself. The trailing was no more problematic on this title than on most 60Hz monitors despite the fairly shadowy aesthetic. Another good test for a typical game scene that may be affected by trailing from dark objects was close-in dogfighting on Lock On: Modern Air Combat. The game was very playable overall and even during intense dogfighting our performance wasn’t impeded by the EW2420’s responsiveness. The most palpable traily occured when rapidly turning against dark-coloured aircraft. The most extreme case we found of this ‘black ghosting’ (or just ghosting in general), however, came when looking down some thermal optics on Armed Assault 2: Operation Arrowhead.

You can see the actual image (white man on right) as well as a grey ghost image displaced some distance to the left. Even slower mouse movements caused similar ghosting in the instance, but with less extreme displacement. The overall experience and atmosphere that the EW2420 created on night missions on Arma2, however, was nothing short of spectacular. As you will read later on in the ‘conclusion’ the contrast on this game at night was very special indeed.

On The Girl with the Dragon Tattoo, which impressed us with its contrast and (suitably displayed) grittiness, we found that trailing was no more evident than on most TN panels we’ve tested the movie on. Likewise the trailing on Futurama was characteristic of most monitors we’ve tested with the frame rate at which the movies are produced being more of a limiting factor.


It is clear from the outside that the BenQ EW2420 is aimed at the home user. Its glossy black bezel, fixed glossy oval stand and range of ‘entertainment’ oriented inputs all help the EW2420 blend into this crowded sector. What distinguishes the EW2420 from other monitors in this niche and at this price range, however, is the *VA panel that lies beneath. This promises far superior contrast, superior colour reproduction and superior viewing angles on paper – and these promises were not broken in practice, either. The contrast and vivid but varied colours really did add an extra layer of immersiveness to the game and movie titles we tested whilst the semi-gloss coating provided an excellent and harmonious solution to the dulling matte screens and overly reflective glossy screens that polarise the market. The excellent colour and contrast performance could also make this a suitable choice for photography and design-type applications; although for colour-critical work IPS (In-Plane Switching) models still offer a slight edge in terms of consistency and could be a better choice (budget notwithstanding).

One area where the EW2420 falls behind slightly, however, is the responsiveness of the panel. The issue of responsiveness is a little thorny as it is highly subjective in nature and dependent on the type of applications you use and at what ‘level’ you use them. The prime area of concern is, understandably, fast-paced gaming such as certain FPS titles. We actually purchased this monitor ourselves due to high demand for a review, lack of availability of review samples and our need for a good all-round monitor for one of our systems. Based on our previous experiences with *VA panels we knew we were taking a bit of a gamble. When we first got it we had certain preconceived notions in our head and we were poisoned against the monitor – looking out for every opportunity we could to slate it for lack of responsiveness. Fortunately any reservations we had about the panel and its suitability for intense gaming soon evaporated as we used the monitor a little more. A particularly fantastic moment, which we hinted at earlier but didn’t really discuss, occurred on Armed Assault 2: Operation Arrowhead during a multiplayer mission set. This was set in the fictional Takistani desert in the dead of night. We were initially using this as an opportunity to see how the response time faired in particularly dark scenes; but once the mission got going we were simply in awe of the spectacular visuals being beamed into our eyes. The pitch darkness of the night sky was in itself wonderful to behold, as were the bright white stars and the moon above. What was truly extraordinary, though, was the pure brilliance of the glowing green light of tracer fire and occasional burst of visual glory from explosions set against the blackness above.

When using the BenQ EW2420 it is very easy to forget that this is, according to its price, a ‘budget monitor’. At around £170 ($250) the BenQ EW2420 really does tick a lot more boxes than the competition, offering an outstanding visual experience. It also brings home the advantages of LED-backlighting (such as improved energy efficiency, lower heat production and less physical depth) without suffering from the same toy-like feel that other ‘budget’ LED-backlit monitors suffer from. Whatever your intended use, the BenQ EW2420 should certainly be a serious consideration if you’re looking for a stunning sub-£200 display.

Positives Negatives
Excellent contrast with deep blacks, brilliant whites and good distinction of shades between
Stand lacks height, swivel and rotation adjustment
LED backlit for increased energy efficiency, longer backlight lifetime and lower heat output
OSD navigation could be (a lot) better
Good colour reproduction with pleasing vibrancy – semi-gloss coating reduces ‘dulling’ effect
Minor reflections from semi-gloss coating
Good viewing angles (no significant colour shift) Slight gamma shift may limit suitability for colour-critical work
Very attractive price tag Responsiveness is not quite as good