Author: Adam Simmons
Date published: July 18th 2012
BenQ are one of a dwindling number of manufacturers to release monitors using Vertical Alignment (VA) panels. Indeed they were the first manufacturer to combine VA panels with the increasingly ubiquitous LED backlight. A particular strength of this panel type is contrast performance with measured static contrast coming in at around 3-5 times that of competing TN and IPS technologies. Response times, on the other hand, are really the Achilles heel of the VA panel and BenQ’s previous models have certainly suffered in this regard.
The BenQ GW2750HM is the fully featured 27” member of the company’s latest GW series of VA panel monitors. BenQ are keen to promote not only the contrast potential of the GW series (claiming 5000:1 static) but also native support for 8-bit colour per channel – a definite rarity for modern LCDs of this price. Furthermore they make a rather ambitious claim of a 4ms grey to grey response time. In this review we will put the GW2750 through its paces and see just how valid these claims are in practice.
The BenQ GW2750HM’s basic specifications reveal some interesting and quite bold figures, including a 5000:1 static contrast ratio and 4ms grey to grey response time. One particular point of interest, which could change how this product is viewed, is the current market price in the UK compared to the US. Typically monitors at their ‘base price’ (without state-specific tax) are somewhat cheaper in the United States compared to the United Kingdom. At time of writing the monitor typically retails at around £190 including VAT in the UK, whereas in the US it typically retails for around $400 (£256).
The specifications are listed below with key ‘talking points’ highlighted in blue for your reading convenience.
Features and aesthetics
From the front the BenQ GW2750HM has a fairly plain look to it. Glossy black plastics, oval stand base, relatively thick bezels (around 26mm at the side) and tactile buttons running along the bottom of the right side. Essentially the styling is very similar to the EW2420 rather than the more adventurous EW30 series.
One important and slightly disappointing difference is the absence of a low haze (13% haze value) ‘semi glossy’ screen surface as found on previous BenQ VA panels. Such a screen surface helps provide a smoother and slightly more vibrant image whilst handling glare reasonably well (see this article). BenQ (or panel manufacturer AUO) have instead gone for a regular matte surface which appears quite similar to Samsung’s typical matte surfaces as illustrated below. This is certainly nowhere near as obtrusive or ‘grainy’ as you’d find on most IPS monitors but is more so than on BenQ’s previous VA monitors.
The OSD (On Scren Display) is set up in BenQ’s usual style and is controlled by buttons on the side of the monitor. The menu system is a little awkward to navigate through due to delays and general lack of responsiveness. Having the up arrow represent right and the down arrow left also takes a bit of getting used to. Adding to this frustration is the fact that the quick access keys are set to volume (up arrow) and Senseye image presets (down arrow) rather than the more commonly appreciated brightness. These niggles aside the menu offers some important image controls such as brightness, contrast, gamma modes and colour channel adjustment. A run-through of the menu system is given in the video below.
The side of the monitor is also quite plain without any extras like USB ports. The right side features the OSD control buttons and power button with accompanying LED that glows green during normal operation and amber to indicate standby. The buttons protrude out slightly so are visible and easy to see from the front whilst the power LED remains fairly unobtrusive from the front. The buttons also have central dimples to aid touch navigation in the dark. Being LED-backlit the monitor is fairly slender – but BenQ haven’t gone overboard on this aspect and include VESA mounting holes. According to our measurements the monitor is 26mm at thinnest and 56mm at thickest point.
The rear of the monitor features an up-firing speaker and ventilation grill, 100 x 100mm VESA holes, a central stand quick-release button and Kensington lock. BenQ have been reasonably conservative with their inputs but include the main trio of HDMI, DVI and VGA. An audio input (line in), audio output (headphone jack) and AC power input are also located here. The ports face downwards to facilitate wall-mounting.
Using the default settings the image was overly bright and somewhat bleached with a relative lack of intensity in reds and oranges in particular. We used the Lagom website, some familiar desktop images and backgrounds alongside a Spyder4Elite colorimeter to help fine-tune the image on the GW2750HM. After testing out a multitude of settings in combination we settled for the following:
Brightness= 50 (according to preferences and lighting – this was on a bright summer day)
Contrast= 50 (lower is duller, higher bleaches the image)
Color Temperature= User Mode
This provided an image that was richer and better balanced. Central gamma average 2.3 with ‘sagging’ in the mid-tones to give a lower output brightness for a given shade than you’d expect from the 2.2 standard. For the purposes of our testing this wasn’t a problem and actually invited a bit of extra vibrancy to the image. Those demanding particularly stringent gamma regulation would need to perform a calibration using a colorimeter or similar device. Failing that ‘Gamma 4’ seemed the best preset to use as ‘1’ and ‘2’ provided gamma that was far too low (1.8), ‘3’ that was slightly too low (2.0) and ‘5’ that was too high on average (2.5).
When thinking about calibrating or ‘tweaking’ the BenQ GW2750HM by all means use our settings as a starting point. Do be aware that individual units, different GPUs and connection types (particularly HDMI) can affect results. For the purposes of this review we used an AMD Radeon 7950 connected to the monitor by DVI.
Contrast and brightness
Using a KM CS-200 ‘Chroma Meter’ we measured the luminance of ‘white’ and ‘black’ under a range of settings and calculated the consequent contrast ratio. For the first 6 rows of the table below only brightness was altered and all other settings remained in their ‘Standard’ mode defaults. The highest recorded white luminance, lowest recorded black luminance and highest overall contrast ratio are highlighted in black on the table and the results under our test settings in blue.
|Monitor Profile||White luminance (cd/m2)||Black luminance (cd/m2)||Contrast ratio (x:1)|
|‘Standard’, 100% brightness||371||0.14||2650|
|‘Standard’, 80% brightness||319||0.12||2658|
|‘Standard’, 60% brightness||268||0.10||2680|
|‘Standard’, 40% brightness||216||0.08||2700|
|‘Standard’, 20% brightness||164||0.06||2733|
|‘Standard’, 0% brightness||111||0.04||2775|
|Test settings, 66 brightness, 50 contrast (other settings customised)||225||0.09||2500|
Contrast performance on the GW2750HM was strong despite falling far short of the 5000:1 static contrast ratio specified for the panel. The average contrast ratio under ‘Standard’ settings with brightness only adjusted was 2699:1 – something that only VA LCD panels can muster. Using our test settings contrast was still strong at 2500:1. Black levels were elevated slightly in most of the preset modes with ‘sRGB’ mode yielding the highest contrast ratio at 2530:1. ‘Eco’ mode provided a frankly rubbish contrast ratio of 582:1 and seemed to deliver black luminance exceeding ‘Standard’ 100% brightness whilst delivering only 99 cd/m2 at peak. In contrast to this, 371 cd/m2 was delivered at 100% brightness in ‘Standard’ mode which is exceptionally bright and far exceeds the 300 cd/m2 specified by BenQ. The minimum luminance under ‘Standard’ settings was a touch on the high side at 111 cd/m2 – the lowest brightness was 99 cd/m2 as recorded under ‘Eco’ mode but brightness controls are locked and contrast is very poor. The Senseye preset modes are generally best avoided as they only confer disadvantages to the image including reduced contrast and fewer adjustment options.
The monitor also features a ‘Dynamic Contrast’ mode which can be activated under the ‘Game’, ‘Movie’ and ‘Photo’ presets and set in intensity between 1 and 5. This does what it is supposed to and is there if you need it. Even though this customisable level is one of the best approaches we’ve seen to Dynamic contrast we still see it as a compromise given the mixed makeup of scenes with ‘dark’ and ‘light’ intertwined. With static contrast levels approaching 3000:1 there is not really any need to use a Dynamic Contrast mode anyway.
Another factor to consider is how contrast and brightness varies across the screen, not just how the centre looks to a colorimeter. We observed a minor hint of backlight bleed in the bottom corners of the screen. This was only visible in a darkened room and manifested itself as a lighter grey compared to the darker black elsewhere on the screen – so not obtrusive or even particularly noticeable in general use. A slight purple sheen could also be observed at the far edges if you move your head off-angle. This is like a much more subtle version of what is commonly observed on IPS panels and dubbed ‘IPS glow’. This ‘VA glow’, if you like, is only really visible when viewing the screen from quite an off-centre angle and is not visible from a normal seated position even on a screen this large. This phenomenon is shown in a video in the ‘viewing angles’ section of the review.
Variation in brightness must also be considered on other shades and this is best demonstrated at the opposite end of the range by viewing pure white across the screen. Using a Spyder4Elite colorimeter we measured the luminance at 9 equally spaced quadrants running across the screen and compared the luminance at each quadrant with the brightest measured point. The readings given in the table below were taken under our test settings.
Luminance uniformity table
Results here were quite pleasing overall. The brightest point of the screen was reported as ‘quadrant 8’ (bottom central region) with a reading of 228 cd/m2. The highest deviation occurred at ‘quadrant 3’ (top right) where a luminance of 201.7 cd/m2 was recorded – 12% dimmer than the brightest point. Elsewhere the monitor was 6-8% dimmer than the brightest point with the exception of a mere 2% deviation in the central region (‘quadrant 5’) where 224.3 cd/m2 was recorded. These deviations are relatively minor and did not manifest themselves visibly in any of our testing. This doesn’t take into account shift in colour or gamma which is explored subsequently but given the price point of the monitor these deviations were more than acceptable. As with the black uniformity individual units may vary in this regard.
The deviations in brightness can also be represented visually as shown in the contour map below. This combines recorded values with extrapolated values to illustrate differences in luminance across the screen. The brightest point (‘quadrant 8’) appears the lightest shade of grey on the map with darker grey shades representing decreasing luminance and thus deviations from this value.
Luminance uniformity map
The strong contrast performance demonstrated quantitatively was also demonstrated in our subjective testing. The first game title used for assessing contrast performance was Battlefield 3 where an excellent level of detail could be seen in dark areas. Subtle detailing on the weapon models and objects in the environment were visible in shaded spots regardless of their position on the screen. There was no noticeable unintended extra detail or gamma enhancement going on either so everything was represented much as it was intended. Distinction between bright elements (such as fires, explosions, tracers, the engineer repair tool and lights) with the surrounding dark was very good. These bright elements did show a very good relative intensity but also lacked ‘luminescent purity’ due to the slight haze of the screen surface.
The second game title, Dirt 3, showed excellent low-end detail as well with subtle elements such as grills and material textures visible inside and outside the car. Individual branch and leaf structures were also visible in shaded areas around the track without any additional unintended detail or enhancement. The glare from the sun during the day and car headlights at night were suitably dazzling – although again weren’t entirely ‘pure’ due to the screen surface. This was also slightly noticeable on light textures, in particular, such as the sky and snow. These were given a bit of an unintended grainy appearance but this was not particularly bad. The screen surface used on the GW2750HM, we should reiterate, is nowhere near as grainy or high-haze as you’d find on many IPS monitors or even some TN panels. Having said that the comparison does need to be drawn between this matte surface and the low-haze surfaces that BenQ had previously used on their VA panel monitors; these low-haze surfaces were better in this regard.
The strong contrast performance was also reflected on the Blu-ray movie ‘The Girl Who Played with Fire’. There was no noticeable loss of detail at the low-end and good intensity at the high end. The contrast between roaring flames and the dark surroundings was particularly intense. This film is also shot in a 2.35:1 aspect ratio and black bars are drawn at the top and bottom of the screen. These bars did appear rather black and weren’t marred by any excess backlight bleed. To explore things objectively once again and round off this section we used the Lagom LCD tests for contrast which are good at exploiting any weaknesses.
The GW2750HM’s colour gamut (red triangle) was compared to sRGB reference (green triangle) under our testing settings using the Spyder4Elite’s reporting functionality. The results are shown in the image below.
The colour gamut corresponds roughly with the sRGB reference although coverage of green shades is a little patchy. This 2D representation of the colour gamut also suggests some extension in other green and orange shades. This is quite a usual result for a typical WLED backlight and doesn’t really give you a great deal of detail about the overall colour performance of a monitor – only the potential range of colours that could be produced. To assess the colour performance from an entertainment perspective we used our usual game and movie titles, the first of which was the well-known FPS Battlefield 3. There was a good level of vibrancy and very good shade variety shown here, within the confines of the game engine. Environments looked as intended with a range of minty and slightly deeper greens, neutral rocky greys and earthy browns. Some good vibrant elements were also mixed in; glowing orange fires and bright yellow warning signs stood out particularly well. Some of the reds within the game could have done with a touch more richness and so could some of the neon blue, orange and red HUD elements. The colour experience was quite pleasing overall, though.
Our second game test title was Dirt 3. From the sunkissed red earth and dusty green and kharki vegetation of Kenya to the lush forest of Finland and Michigan, the environments were well represented with good shade variety and colour consistency. There was a slight weakness in some of the deeper greens as they appeared just a touch yellow and not as lush as we’ve seen. Overall things in the environment looked ‘in place’, however. The car paint jobs and adverts around the track had a pleasing vibrancy to them with some good bright pinks highlighter yellows and bright cyans. Some of the deeper blues showed a very slight purple hint to them and some of the oranges and reds could have benefited from just a little more depth. Having said that these were still stronger than on many monitors we’ve tested so maybe that’s being pedantic.
We also tested the colour performance of the GW2750HM on two movies. First up was the Blu-ray of ‘The Girl Who Played with Fire’. This had good natural-looking and varied environments, appropriate range and saturation of skin tones and some decent vibrancy to elements such as roaring flames and florescent lights. The second title, Futurama: Into the Wild Green Yonder provides a feast of colour and is one of our favourite tests for colour reproduction. There was a good intensity to colours with bright yellows and greens, deep purples and neon pinks standing out in particular. This was particularly impressive on planets, spaceships and cosmic light surrounded by deep black space. Pastel shades were shown with a very good variety with distinct purple, peach and brown skin tones and character clothes having a distinct identity. There was a degree of shift for a given shade, depending on its position on the screen. This was more subtle than on a TN panel monitor of this size but more pronounced than on 27” IPS or PLS panels.
From our testing it seemed that colours were more consistent than on 27” TN panel monitor but less so compared to 27” IPS and PLS panel monitor with particular weaknesses at the sides. This is much as you’d expect on this panel type and was affirmed by the Lagom LCD tests for viewing angles. These tests are very good at highlighting even subtle variations in colour that would be particularly important for colour-critical tasks, for example.
- The purple block appeared a predominantly lilac with a pink hue towards the side edges.
- The red block appeared a deep red for the most part with a pink tint towards the bottom corners of the screen.
- The green block appeared quite a solid green through with a slight yellow pollution. It was impressively consistent.
- The blue block as a good solid blue throughout.
- The Lagom text test confirmed that the gamma curve of the GW2750 has some degree of viewing angle dependency, particularly horizontally. It appeared largely a blended grey with a bit of red tint creeping in at the sides and bottom corners in particular and a slight green hue towards the top. The blatant flashing contrast between green at the top and red at the bottom wasn’t there so this is certainly a better result compared to TN matrices.
The following video shows the Lagom text test, a mixed desktop background and dark desktop background from centralised and decentralised positions. It is difficult to show some of the subtle changes to the images that can be perceived by eye but you can certainly see that shifting occurs. This is quite obvious on the Lagom text test (remember it would ideally appear blended grey at all times) and also from the mixed desktop image which shows a shift in hue as the viewing angle is altered. This is again less pronounced than on a TN matrix and you don’t get the significant vertical colour inversion common to TN panels. The dark desktop image reveals this slight purple ‘VA glow’ that was alluded to in the ‘contrast and brightness’ section.
BenQ were very determined to push home the notion that responsiveness has been improved on the GW series compared to their previous VA iterations. They even specified a 4ms grey to grey response time which should of course be taken with a bucket of salt but does get you wondering what you’re in for as a monitor reviewer. First off we used PixPerAn (Pixel Persistence Analyser) and a camera at high ISO to gauge pixel behaviour during some typical grey to grey transitions at high speed. The tempo of PixPerAn was set as high as it would go to represent the ‘worst case’ scenario as far as this test is concerned. The pictures below are taken using the three different settings for AMA (Advanced Motion Acceleration), BenQ’s pixel overdrive feature; ‘OFF’, ‘High’ and ‘Premium’.
Ghosting (AMA 'OFF')
Ghosting (AMA 'High')
Ghosting (AMA 'Premim')
It was clear straight away that BenQ had made vast improvements in pixel responsiveness compared to their previous VA panel models such as the EW2730V. With AMA set to ‘OFF’ you can see a bold first trail, a second trail and even a faint third trail. Enabling AMA ‘High’ pretty much eliminated the third trail and made the second trail fainter whilst the initial trail remains similar. Setting AMA to ‘Premium’ makes the second trail very faint and changes the nature of the initial trail somewhat. It takes on a slightly woven appearance that is indicative of some RTC (Response Time Compensation) errors which are common where grey to grey acceleration is particularly aggressive. Overall this mode offers the best motion performance which is quite noticeable when gaming and offers a vast improvement over earlier BenQ VA monitors.
Battlefield 3’s on-foot action was reasonably smooth and certainly much more playable than on earlier AMVA panels. There was a bit of a blur evident when moving the mouse quickly or strafing but we found this pretty tolerable. There was no exaggerated ‘smearing’ or smokey trails on this title as you often see with such panels, but there was some mild overdrive trailing visible in a minority of cases. The most obvious example of this could be observed whilst strafing past a light object with clouds in the background as demonstrated in the following video. It isn’t too clear in the video but observe the right side of the tree whilst the character strafes right.
Upping the pace of action a bit and driving a nimble vehicle caused a greater degree of blurring (trailing or ghosting if you prefer), particularly whilst cornering. This was not too severe really and overall the level of trailing on this title seemed quite comparable to modern IPS panel models with pixel overdrive, such as the Dell U2412M.
We also took the monitor for a spin on Dirt 3. With its frequent high-speed meandering and a good range of environments, Dirt 3 proved to be an even better title for testing pixel responsiveness on the BenQ GW2750HM. During race game modes, trailing was comparable to an overdriven IPS panel for the most part – blurring was certainly there in the background, even during gentle cornering, but was not massively distracting. This blurring became a bit more exaggerated on the snow-covered tracks of Norway and Colorado, particularly where dark red, blue and black objects were dotted around the track. The trailing in these cases started resembling more of a smear, more exaggerated than on a modern IPS panel but not to the extent that we’ve seen on previous AMVA panels. Further weaknesses were exploited on the fast-paced Gymkhana mode where contrasting colours would blur into one another and intermediate ‘fringe’ colours would also become visible. It is tough to be overly critical given that this game mode can even put a bit of a strain on modern TN panels, though.
We observed no particular problems with excessive blurring during movies. The limited frame rate at which these are shot and run is really the limiting factor in fluidity and limits the pace of action to well within the ‘comfort zone’ of the BenQ’s pixels. To round off the responsiveness testing we also looked at input lag which has no bearing on movies but is one of the factors influencing how responsive a monitor ‘feels’ in relation to user input (whilst gaming, for example). Using a similar protocol to that in our other recent monitor reviews we were able to estimate the input lag of the BenQ GW2750HM. We measured an average of 7.2ms (just under half a frame). This is a pleasingly low value and shouldn’t cause any issues – again this is much better than what you generally see from VA panel monitors.
The BenQ GW2750HM continues the company’s drive to provide an affordable alternative to the ubiquitous TN panel for both the home and office user. With an increasing range of affordable IPS panel monitors to go alongside the TN models, VA has really lost favour recently and is becoming quite a rare breed outside of the TV market. BenQ have always been very clear in their marketing direction for their Vertical Alignment displays – pressing key advantages such as ‘true’ 8-bit colour performance and the highest static contrast you’ll see in LCD form.
The GW2750 delivered these advantages. Although contrast was roughly half as strong as specified for the panel, with an average of around 2700:1 you are firmly in territory that IPS, PLS and TN matrices cannot touch. Colour performance was also pleasing once everything was set up correctly with a good combination of vibrant colours and a pleasing variety of more muted colours. Due to the native 8-bit performance there was no noticeable dithering, either, resulting in a good solid look to colours and no major gradation issues. It was a bit of a shame to see the loss of the low-haze matte surface in place of a ‘regular’ one, though.
One particular weakness of VA panels is traditionally responsiveness – this is particularly true for the relatively affordable AMVA variety favoured by BenQ. Fortunately there has been real significant improvement in pixel responsiveness for the GW series. In both our objective and subjective assessment performance in this area was pretty much on par with modern IPS panel monitors without grey to grey acceleration – and that is a good improvement to see.
Overall the BenQ GW2750HM is an interesting proposition, offering some unique advantages. The colour consistency may not be up there with In Plane Switching panels and the responsiveness not up there with Twisted Nematic panels but the contrast performance comfortably trumps both. Given the price there is a lot to like about this monitor. It is certainly one to consider if you’re after a 27 inch monitor that won’t break the bank and offers a good all-round performance.
|Strong contrast performance with good black depth and plenty of brightness
||Contrast ratio significantly below that specified (but still excellent)
|Good colour reproduction with a strong shade range and good vibrancy||Colour consistency and viewing angles not as good as on IPS models, some vibrancy and clarity potential wasted due to screen surface|
|Pixel responsiveness massively improved over previous models and input lag pleasingly low
|| Some pixel transitions lag behind other panel types so there is still room for improvement
|Competitive pricing given the screen size, more so given performance||Limited stand adjustability, fairly simplistic aesthetics and not too many connections|