Introduction

The VP2770-LED is the latest addition to ViewSonic's successful professional line-up of monitors which has been around for many years. This new screen is an ultra high resolution 27" model, boasting a 2560 x 1440 resolution, a W-LED backlight unit and a range of high end features. The product information provided by ViewSonic talks about its wide range of connectivity and ergonomic options which have been a feature of the VP series for a while. The screen comes factory calibrated as well since it is largely aimed at professional users and ViewSonic's spec talks about a 'SuperClear' IPS panel, a 1.07 billion colour depth and the wide viewing angles provided by the panel technology. In fact some of these specs are not entirely accurate, but we will talk about that later on in the review (see our panel and backlight section).

ViewSonic's website states: "The VP2770-LED is the ultimate professional grade LCD monitor for design, digital photography, video production, architecture or any other application where true colour and total screen viewing is essential. Flexible connectivity options include DisplayPort, HDMI�, Dual-Link DVI and VGA, along with 4 USB ports for connecting your peripherals. The ergonomic stand provides height adjust, swivel, tilt and pivot for maximum comfort. Backed by ViewSonic's best industry leading pixel policy and full 3-year limited warranty, the VP2770-LED is the right choice for your professional display needs."

Specifications and Features

The following table gives detailed information about the specs of the screen:

Manufacturer website Link

The VP2770-LED offers a very good range of video connections which is great to see. There are HDMI, Dual-link DVI-D, D-sub and DisplayPort provided for video interfaces. With the screen offering a 2560 x 1440 resolution though only the DL-DVI and DisplayPort connections can support the full resolution due to bandwidth limitations over VGA and HDMI. It is nevertheless nice to see VGA and HDMI provided for users who want to connect other devices, particularly external Blu-ray and DVD players. The digital interfaces are HDCP certified for encrypted content as well. There is also an audio out connection for connecting headphones / external speakers if you wish to take the sound from the HDMI or DisplayPort inputs. There are no integrated stereo speakers on this model it should be noted.

The screen comes packaged with a dual-link DVI, VGA and DisplayPort cables which is useful, although there is no HDMI cable provided with the screen unfortunately, presumably due to cost saving measures. The screen has an internal power supply and so you only need a standard kettle lead (provided) to power the screen. There is a 4-port USB hub provided as well, with 2 ports on the back and 2 ports on the left hand side of the screen. Two of these are USB 2.0 and two are USB 3.0 in fact. I'm not sure why they didn't just provide all 4 as USB 3.0 given they are backwards compatible anyway. The USB cable to connect back to your PC to power these ports is provided in the box.

Below is a summary of the features and connections of the screen:

OSD Menu

 
Above: view of OSD operational buttons. Click for larger version

Power Consumption

In terms of power consumption the manufacturers spec states standard usage of 40W. They do not list a usage when the screen is in standby mode.

We tested this ourselves and found that out of the box the screen used 39.7W of power while at its default brightness setting of 100% and in the 'standard' ECO mode setting. At the lowest brightness setting in this ECO mode, power consumption was reduced to 17.6W. After calibration in the 'user color' mode, the brightness had been set at 20% to achieve the desired luminance and the screen returned a power consumption of 21.9W. In standby the screen used 0.6W of power.

I have plotted the results of these measurements on the graph below:

The screen contains an ECO mode setting available in the 'manual image adjust' menu as shown above. The default mode is standard which we have already measured above. By switching to the other modes, the maximum brightness of the backlight seems to be reduced and capped to a lower level. This isn't done by changing the default brightness setting however, as you still have full control over the 0 - 100% range in the main OSD menu. It seems to cap the top brightness at a lower setting when you move to 'optimize', and then again when you move to 'conserve'. This in theory should give you a wider overall range of adjustments possible from the backlight which we will look at later on in our contrast stability and brightness section. We left the brightness setting at 100% here and simply switched to the 'optimize' and 'conserve' settings to measure the impact they had on power consumption. The manufacturer specifies 30W usage in optimize mode and 22W usage in conserve mode, both of which seem to be pretty accurate in reality.
 

Panel and Backlighting

Panel, Colour Depth and Coating

The ViewSonic VP2770-LED use a 27" Samsung LTM270DL02 Plane to Line Switching (PLS) panel. The panel offers a native 8-bit colour depth and a 16.7 million colour palette. We made reference to the discrepancy here in our introduction section when comparing the reality with what is talked about in the specification and product pages. ViewSonic for some reason list the panel being used as 'SuperClear IPS' and the term IPS is used in the spec lists as well. However, in reality you will see from the service menu that the screen is actually using a Samsung PLS panel. In reality, PLS and IPS offer very similar performance characteristics and seem to be two terms being interchanged by several manufacturers at the moment. Asus have done the same with their recent Asus PB278Q screen where they talk about both technologies. It seems the market is starting to interchange the terms, making it a little tricky to actually identify the real panel technology being used. It is Samsung who manufacturer PLS panels as a rival to the popular IPS panels, made mostly by LG.Display. Here, the VP2770-LED actually uses a Samsung PLS module, so don't be confused by the listed spec and talk of IPS in the marketing material. We clarified with ViewSonic that the term IPS was being used here since it is more well-known and understood in the market.

The panel is confirmed when accessing the factory OSD menu as shown above.

ViewSonic talk about a 1.07 billion colour depth in some of their website information and the use of a "10-bit" panel. In fact in some places in the specs and website they say the screen offers a "1.7 billion" colour depth which is wrong and probably a typo. If the panel was a 10-bit module, it would support 1.07 billion colours (1024 x 1024 x 1024) and not 1.7 billion which doesn't add up. However, having studied the detailed panel spec sheet for the LTM270DL02 module we know the panel is in fact a native 8-bit module. After speaking with ViewSonic they have confirmed that an additional Frame Rate Control (FRC) stage is added by the scaler to give support for "10-bit" colour depth, despite the 8-bit native panel. This has been used elsewhere by other manufacturers as well and is an alternative to using an 8-bit panel which has a FRC stage applied at the panel side.

It's all very well saying a panel is capable of "10-bit" colour depth as opposed to an 8-bit colour depth, but you need to take into account whether this is practically useable to you, and whether you're ever going to truly use that colour depth. You need to have a complete 10-bit end to end workflow in order to make use of this which includes a 10-bit supporting application, operating system, graphics card and software. This is still quite rare and reserved really for high end equipment and professional uses. Nevertheless the 10-bit colour support is there for future uses and for if you do have the necessary workflow to support it. The use of FRC at the scaler side to simulate this 10-bit colour depth is common and while it's not a 'true' 10-bit panel, which are very rare and expensive, many users  would not notice a difference in real terms anyway if managing to achieve a working 10-bit workflow.

ViewSonic also talk about their so-called "SuperClear engine" (also sometimes called "UltraClear technology") on this model. Speaking with ViewSonic about this we are told this is a special firmware for helping to make the image details and resolution even more refined apparently. It will be also included in other future IPS (and PLS) based models featuring the SuperClear name. We will look at this a little later on in the review as well.

The screen coating on the VP2770-LED is an anti-glare (AG) offering. Like other PLS panels such as the Samsung S27A850D, the coating is very light and so does not give the dirty or grainy appearance of many IPS based models (with the exception of some recent AH-IPS models like the Dell U2713HM and NEC P232W). Being a light AG coating it retains the anti-reflective nature but produces clean and crisp images. Those familiar with other matte finish PLS panels will find the same level of AG coating here on the ViewSonic model.
 

Backlighting and Colour Gamut

The VP2770-LED uses White-LED (W-LED) backlighting producing a colour space approximately equal to the sRGB reference. This means the screen is considered a 'standard gamut' backlight type. Studying the detailed panel spec sheet confirms a coverage of 81% NTSC, 78.1% Adobe RGB and 99.5% of the sRGB colour spaces. A wide gamut screen would need to be considered by those wanting to work further outside of the sRGB colour space of course.
 

PWM Flicker Tests at Various Backlight Brightness Settings

100%                                                 50%                                                      0%

We tested the screen to establish the methods used to control backlight dimming. Our recent article talks in more details about a common method used for this which is called Pulse Width Modulation (PWM). A series of photos was taken using the method outlined in the article. These were taken at 100%, 50% and 0% brightness settings. This allows us to establish 1) whether PWM is being used to control the backlight, 2) the approximate frequency at which this operates, and 3) whether a flicker may be introduced or potentially noticeable at certain settings.

A thin white line was shown on an all-black background and a photograph was taken at a slow shutter speed of 1/8 second (in this example) as the camera was scanned left to right in front of the screen. This produces a series of white lines which can be used to identify the frequency of the PWM and how quickly the backlight is cycled on and off. The higher this frequency, the less likely you are to see artefacts and flicker. The duty cycle (the time for which the backlight is on) is also important and the shorter the duty cycle, the more potential there is that you may see flicker. Please remember that not every user would notice a flicker from the backlight but it is something to be wary of. It is also a hard thing to quantify as it is very subjective when talking about whether a user may or may not experience the side effects. We are able to at least measure the frequency of the backlight using this method and tell you whether the duty cycle is sufficiently short at certain settings that it may introduce a flicker to those sensitive to it.

Interestingly the ViewSonic VP2770-LED does not use PWM at all for dimming of the backlight. Even at 0% brightness there was no sign of the usual splitting of the white line that you'd expect to see in these tests. We carried out the checks at an even slower shutter speed which returned the same result. This is great news for those who are affected by flickering backlights and suffer from eye fatigue and eye strain. There are very few monitors which don't use PWM for backlight dimming although we have started to see a few more recently. The HP ZR2740w, DGM IPS-2701WPH, Samsung S27B970D and Dell U2713HM spring to mind as other 27" models which do not use PWM.

Testing Methodology

An important thing to consider for most users is how a screen will perform out of the box and with some basic manual adjustments. Since most users won't have access to hardware colorimeter tools, it is important to understand how the screen is going to perform in terms of colour accuracy for the average user.

I restored my graphics card to default settings and disabled any previously active ICC profiles and gamma corrections. The screen was tested at default factory settings using the DVI interface, and analysed using an X-rite i1 Pro Spectrophotometer (not to be confused with the new i1 Display Pro colorimeter) combined with LaCie's Blue Eye Pro software suite. An NEC branded and customised X-rite i1 Display 2 colorimeter was also used to verify the black point and contrast ratio since the i1 Pro is less reliable at the darker end.

Targets for these tests are as follows:

• CIE Diagram - validates the colour space covered by the monitors backlighting with the black triangle representing the display

• Gamma - we aim for 2.2 which is the default for computer monitors

• Colour temperature / white point - we aim for 6500k which is the temperature of daylight

• Luminance - we aim for 120 cd/m², which is the recommended luminance for LCD monitors in normal lighting conditions

• Black depth - we aim for as low as possible to maximise shadow detail and to offer us the best contrast ratio

• Contrast ratio - we aim for as high as possible. Any dynamic contrast ratio controls are turned off here if present

• dE average / maximum - as low as possible. If DeltaE >3, the color displayed is significantly different from the theoretical one, meaning that the difference will be perceptible to the viewer. If DeltaE <2, LaCie considers the calibration a success; there remains a slight difference, but it is barely undetectable. If DeltaE < 1, the color fidelity is excellent.

Default Performance and Setup

Default settings of the screen were as follows:

ViewSonic VP2770-LED - Default Factory Settings

   

The screen comes out of the box in the 'native' color adjust preset mode, although there is an additional preset which carries a factory calibration which we will test shortly. Default setup of the screen actually felt very good to the naked eye although it was far too bright at its default 100% brightness setting. Colours felt even and not too cold, not too warm. Note that in the 'native' preset mode here the RGB levels are not available to change to the user.

Out of the box the performance of the screen was very pleasing. The CIE diagram on the left confirms that the monitors colour gamut (black triangle) roughly matches the sRGB colour space (orange triangle) but does extend past the sRGB space in some blues and reds, and falls short in some greens. This means there is some slight over-saturation in some shades and some slight under-coverage in others. This doesn't appear to be the monitors native gamut either as we would expect a wider coverage based on previous experience with this PLS panel. We will look at this a little more in a moment.

Default gamma was recorded at 2.2 average, leaving it only 1% out from the target which was excellent. The gamma was a little too high in darker grey shades as shown in the detailed table above. White point was also very close to the target, being recorded at 6576k and being only 1% out again. Note that we are using a spectrophotometer to make these measurements which is not sensitive to the W-LED backlight as some colorimeter devices can be. When using a standard gamut colorimeter not designed to work with modern backlighting units like W-LED, there can be a typical deviance of 300 - 600k in the white point measurement which is why some sources may refer to a different white point in this test incorrectly.

Luminance was recorded at a very high 300 cd/m² which is a too bright for prolonged general use. The screen was set at a default 100% brightness in the OSD menu but that is easy to change of course to reach a more comfortable setting. Changing the brightness will not impact the other areas like gamma and white point. The black depth was a moderate 0.39 cd/m², giving us a mediocre contrast ratio of 777:1. This was ok, but not great, and was quite similar to what we'd seen from the Samsung S27A850D and S27B970D which feature similar versions of the same PLS panel. Colour accuracy was excellent at default factory settings with an average DeltaE (dE) of 1.2, ranging up to a maximum of only 2.4. Along with the very good gamma and white point, this setup was very pleasing, even in this standard preset mode which doesn't carry any specific factory calibration. The only slight disappointments were the colour space coverage and the mediocre contrast ratio.

ViewSonic VP2770-LED - Default Settings, User Color Mode

   

We also tested the default performance in the 'user color' preset. This mode allows you access to the individual RGB channels which will give you more control over the hardware when it comes to calibration. They were all set at 100 by default. The performance in this mode was not nearly as good as we'd seen from the 'native' mode unfortunately. Interestingly the colour gamut was now wider than it had been before, with more extension in reds and blues than we'd seen in the 'native' preset and also an improved coverage in greens. This mode seemed to operate at the monitors native gamut of the backlight, and the colour space coverage looked very similar to what we'd seen from the Samsung S27B970D, using a similar version of the same PLS panel. This also fits in with the fact we know the panel is supposed to cover 81% of the NTSC colour space, extending beyond the sRGB reference which is ~72% of the NTSC space. The monitors default 'native' colour mode must be trying to emulate a smaller colour space closer to sRGB, albeit not achieving it very well unfortunately.

Gamma remained close to the target with 2% deviance overall and with the discrepancy now in the lighter grey tones where it was too high. White point was a little too cool now at 7132k, showing a 10% deviance from the target. Luminance had actually been increased a little in this mode, since the RGB channels were now at 100% each by default (presumably at lower settings in the 'native' mode). This increased the luminance a little to 314 cd/m², and resulted also in a slightly higher static contrast ratio of 802:1. The colour accuracy was unfortunately not as good in this preset mode by default, with average dE of 2.8 and maximum of 11.9. Blues were particularly poor here. This mode would allow you to control RGB levels for calibration though but the 'native' mode carried a far better default setup.

Factory Calibration

The VP2770-LED comes factory calibrated in its sRGB mode as well. Each unit is shipped with an individual calibration report which is specific to that sample. This specifies a maximum dE of <5 and average dE of <3. In addition it is also calibrated for optimised grey scale tracking and gamma curves. The sheet provided with our screen is shown below for reference. Note that this report is only relevant to our specific test unit and they do state that results may vary with each setup and different test equipment.

This report might look very familiar to regular readers. In fact it looks remarkably like the report supplied with the Dell U2713HM, which also carries a very similar factory calibration in sRGB mode. In fact the report seems to be a re-branded report from the same process, with ViewSonic's details and logos substituted in place of Dell's. They have even left part of the Dell monitor name here where it reads "ViewSonic UltraSharp VP2770-LED".

I was interested to see if this factory calibration helped at all with default settings. Note that this is only relevant for the sRGB preset mode available through the OSD menu. You will need to change from the default 'native' preset to benefit from these factory calibrated settings. Having said that, we'd actually seen a great default setup in the native mode anyway.

ViewSonic VP2770-LED - Default Factory Calibration, sRGB mode

   

The factory calibration of the sRGB preset mode was very pleasing on the most part. This mode actually had a colour gamut which was the same as we'd seen in the 'native' default mode. This seems to suggest that both the native and sRGB modes are set up to try and emulate the smaller sRGB gamut as closely as they can, instead of over-saturating colours from the backlights full gamut (seen in the 'user color' mode). However, the colour space coverage is a little off again as we explained before. It doesn't quite match the sRGB space fully.

The average gamma was good again with only 1% deviance from the target. White point was accurate as well with a 6595k reading and only 1% out from the target. Luminance was much lower in this mode and the brightness/contrast controls were now not available in the OSD menu. This seemed to offer a locked luminance at 95 cd/m² which may actually be a little low for some users. At this luminance the contrast ratio was the same as we'd seen before in the native mode, at 777:1. Colour accuracy was again very good with dE average of 1.2 and maximum of 3.4.

While this factory calibration was actually very good, the default setup of the native mode was just as good, but had the added benefit of a control over the brightness setting if you wanted to. It was also a little more accurate in colour reproduction so would probably actually be a better mode for most users to use. This sRGB with its factory calibration might be useful for those who want to switch to another reliable mode, but with a lower luminance.

Testing Colour Temperatures

The VP2770-LED features a range of colour temperature presets within the OSD 'color adjust' menu as shown above. These are not defined as specific temperatures, rather you have a series of options depending on how warm or cool you want to make the image. We measured the screen with the X-rite i1 Pro spectrophotometer in each of the preset modes to establish their colour temperature / white point. All other settings were left at factory defaults and no ICC profile was active. The results are recorded below:

The colour temperature modes offered various different options. The sRGB and Native modes offered a white point very close to our target of 6500k which was good. the 'user color' mode allows you to control the RGB channels, but at its default 100/100/100 setting the white point was a bit cool at 7132k. Adjusting those RGB channels will of course impact the white point accordingly.

Calibration Results

I wanted to calibrate and profile the screen to determine what was possible with optimum settings and profiling. I used the X-rite i1 Pro spectrophotometer combined with the LaCie Blue Eye Pro software package to achieve these results and reports. An NEC branded and customised X-rite i1 Display 2 was used to validate the black depth and contrast ratios due to lower end limitations of the i1 Pro device.

I first of all reverted to the 'user color' mode in the colour preset section of the OSD menu which would allow me access to the individual RGB channels. Adjustments were also made during the process to the brightness control, and to the RGB channels as shown in the table above. This allowed me to obtain an optimum hardware starting point and setup before software level changes would be made at the graphics card level which would help preserve tonal values. After this I let the software carry out the LUT adjustments and create an ICC profile. The screen does not feature a hardware LUT calibration option so other than the OSD alterations, the rest of the process is carried out at a graphics card level in profiling the screen.

This mode operates in the monitors full native gamut, covering 81% of the NTSC colour space and extending beyond sRGB in most shades a little. You may notice some slight oversaturation of colours in some uses, so those looking for a tight control and match of the sRGB colour space may want to use one of the other modes instead. It's not a massive over-coverage so shouldn't present a problem to the average user.

Average gamma had been corrected to 2.2 with 0% deviance according to the initial test correcting the default 2% deviance we'd found in this preset. The 10% deviance in the white point from our target of 6500k had also been corrected here and the colour temperature was now pretty much spot on at 6471k. Luminance had also been corrected thanks to the adjustment to the brightness control, now being measured at 121 cd/m², just slightly out from the target. This also gave us a calibrated black depth of 0.16 cd/m², and a static contrast ratio of 752:1 which was moderate for an IPS panel. Colour accuracy had also been corrected nicely, with dE average of 0.3 and maximum of 0.8. LaCie would consider colour fidelity to be excellent now and there were big improvements compared with the default setup in this preset.

Testing the screen with various colour gradients showed mostly very smooth transitions. There was some slight gradation in darker tones and some very slight banding introduced due to the adjustments to the graphics card LUT from the profilation of the screen. Nothing major at all though. It's worth also commenting on the screen coating in this section of the review. Unlike many IPS based panels, this screen is PLS based and does not feature the usual heavy and aggressive Anti-glare (AG) coating which can sometimes lead to grainy and dirty looking images. Instead it uses a light AG screen coating like other PLS models (Samsung S27A850D for instance) and as a result the colours look more clean and crisp, the image quality is sharp and whites in particular look more pure than they do on heavy AG coated screens. It isn't a full glossy solution which adds another level of clarity and changes the overall feel of the screen, but it is an improvement over the heavy AG coating of some popular IPS screens.

You can use our settings and try our calibrated ICC profile if you wish, which are available in our ICC profile database. Keep in mind that results will vary from one screen to another and from one computer / graphics card to another.

I also carried out the calibration in the monitors 'native' preset mode which had actually returned us a very good default setup out of the box. Here you do not have access to the RGB channels at all, and so the only hardware changes being made are to the brightness control. The other corrections would be carried out at a graphics card LUT level through the profiling process. This mode operates in a smaller emulated colour space, trying to get closer to the sRGB reference but not quite meeting it. It may however help avoid some of the slight oversaturation you may experience at the monitors full native gamut (in the 'user color' mode).

The results were again very pleasing however. Targets for gamma and white point had all been met pretty nicely, correcting the very slight 1% deviance we'd seen in white point out of the box in this mode. The luminance had been corrected to the desired level with the change in the brightness control, and the static contrast ratio was again a moderate 750:1 after calibration. Colour accuracy had been corrected a little from the dE 1.2 average we had seen out of the box, now down to 0.6 dE average. Again testing the screen with various colour gradients showed smooth transitions on the whole, with some slight gradation and some very slight banding in some shades due to the graphics card corrections made.

Again, you can use our settings and try our calibrated ICC profile if you wish, which are available in our ICC profile database. Keep in mind that results will vary from one screen to another and from one computer / graphics card to another.

I also carried out the same process in the sRGB preset mode. This was factory calibrated out of the box and had offered a pretty reliable setup. In this mode we do not have access to the brightness control and we had already seen in our initial tests that the luminance in this mode was ~95 cd/m². As a result we did not define our usual 120 cd/m² target for the profiling, but instead selected "maximum luminance".

The calibration helped correct the slight 1% deviance we'd seen by default in the gamma and white point. Colour accuracy had also been corrected a little from the 1.2 dE average we'd seen out of the box to now be 0.7 dE average. The luminance was retained at the default 94 cd/m² and contrast ratio was 777:1, again not great for an IPS panel but reasonable. This mode offered reliable performance again although the colour space coverage was not quite accurate to sRGB and you are restricted with a defined luminance which cannot be adjusted via the brightness control. Again the 'native' preset mode might provide more flexibility than this mode.

Again, you can use our settings and try our calibrated ICC profile if you wish, which are available in our ICC profile database. Keep in mind that results will vary from one screen to another and from one computer / graphics card to another.

Calibration Performance Comparisons

I've provided a comparison above of the VP2770-LED against some of the other screens we have tested. Out of the box average dE was 1.2 which was excellent really and combined with the very good default gamma and white point represented a great initial setup. This is in the screens 'native' preset mode as well which doesn't officially carry the factory calibration either. It offered a better default setup than Samsung's own PLS based models including the S27A850D (3.6 dE and a fair gamma and white point deviance) and a little better in terms of colour accuracy than the S27B970D (2.6 dE  average, but with a decent gamma and white point setup). What you ideally want from a screen out of the box is a reliable gamma curve, white point and decent colour fidelity. The high default luminance is easy to turn down anyway using the brightness control, and that does not impact the other areas. The ViewSonic VP2770-LED delivers here with a great out of the box setup.

Once calibrated the dE average was reduced to 0.3. This would be classified as excellent colour fidelity by LaCie. It was not quite as low as some of the other screens here which reached down to 0.2 average, but in practice you would not notice any difference here at all. Some of the professional range models from NEC and Eizo for instance are even more accurate. Professional grade monitors like the NEC PA series and P241W also offer other high end features which separate them from some of these other models, including extended internal processing, 3D LUT's and hardware calibration. These comparisons are based on a small selection of tests, so it should be remembered that other factors do come into play when you start talking about professional use. For further information and tests of a high end professional grade screen with hardware LUT calibration, you may want to have a read of our NEC SpectraView Reference 271 review.

The calibrated black depth and contrast ratio of the VP2770-LED were mediocre for an IPS panel really. At 752:1 the contrast ratio was very similar to that which we'd seen from the Samsung S27A850D (PLS based - 761:1) and the Samsung S27B970D (800:1). This seems to be about the limit from this generation of PLS technology, and all three screens are using versions of the same LTM270DL02 panel. Perhaps future generations of PLS will improve in this area to rival some IPS panels which can reach up to around 1000:1. The Dell U2713HM is a good recent example of an IPS panel offering a very good static contrast ratio of 869:1. The AMVA based models here like the 27" BenQ GW2750HM and Philips 273E3QHSB offered very high contrast ratios of 2960:1 and 2412:1 respectively, something which IPS and PLS cannot compete with at the moment.

Contrast Stability and Brightness

Note that we left the screen in the default 'standard' ECO mode for these tests above. The luminance range of the screen was nice and wide. At a maximum brightness setting the screen reached 301.76 cd/m² which was pretty much spot on to the specified 300 cd/m² maximum brightness of the screen. This could be adjusted all the way down to a low 81.49 cd/m² through changes to the brightness control, giving you a very good 220.27 cd/m² adjustment range. This should allow you a good control of the screens luminance for low ambient lighting conditions which is great news. A setting of around 15% should return you a comfortable luminance of ~120 cd/m². Black depth ranged from 0.39 at maximum brightness and went down to 0.10 cd/m² when setting the brightness to 0%.

We have plotted the luminance trend on the graph above. The screen behaves as it should, with a reduction in the backlight intensity controlled by the reduction in the OSD brightness setting. This is pretty much a linear relationship as well.

Static contrast ratio was moderate for an IPS panel, with an average of 777:1. This was mostly stable across the range with some slight deviations at the low end of the adjustment range.

We talked a little earlier on in the review about the 3 ECO mode settings available within the OSD menu, designed to help reduce power consumption. These modes did not act like they might on some other screens, where they often just capped the maximum brightness setting you could use to a defined level. Instead, each of these modes allowed a full 0 - 100% brightness adjustment of their own, but the luminance was noticeably lower in each mode. They also brought about some power savings at the same time as they were designed to do. We ran these same tests again to determine the brightness control range and contrast in each of the other two ECO modes.

Optimize ECO mode

Conserve ECO mode

As you can see, these ECO modes limit the luminance range greatly. In the 'optimize' mode, the maximum luminance is pretty much halved from ~300 to ~150 cd/m². It allows for a lower luminance setting at 0% though if required, down to around 35 cd/m² (81 cd/m² was the limit in standard ECO mode). However, while this might seem like a good way to achieve a lower luminance than was possible in the standard mode, the contrast ratio is crushed somewhat to achieve this. It looks like digital white level adjustments are being made to produce a lower luminance, but contrast ratio is around 520:1 across the brightness range.

A similar story is true for the 'conserve' mode, where maximum luminance is now only ~66 cd/m². This can be lowered to a very low 9.74 cd/m² at 0% brightness, but the contrast ratio is crushed further to ~ 325:1. These modes are not very helpful if you want to maintain a reasonable contrast ratio unfortunately, but may be useful if you need to work in very dark room conditions at certain points.

Dynamic Contrast

We tested the DCR feature in the 'native' color adjust preset mode. The DCR controlled the luminance all the way up to 310.57 cd/m² at the top of the range, and black point down to 0.11 cd/m² at the minimum of the range. This was pretty much the full adjustment of the brightness control from 100 to 0% that we'd seen before in our contrast stability tests. Transitions were nice and smooth and overall it took ~4 seconds to change between the brightest and darkest states. This adjustment range gave us a usable DCR or ~2823:1 which was at least something. This is about the limit you could achieve through the adjustments of the backlight.

So where does the very high 20 million:1 spec come from? We tested the screen again with a 100% all-black screen. After about a second, the screens backlight is actually turned off. We have seen this on some other monitors as well before, and so this is where the 20 million:1 spec comes from. In fact given black depth is then effectively 0.00 cd/m² the DCR would be trending towards infinity:1. However, it should be noted that it would be extremely rare to ever see a 100% black image in real use and so this is more of a theoretical DCR than a realistic, practical DCR. It is something used in the lab to provide a spec for the screen but you are never going to see anything like that kind of DCR in real use.

We would like to start seeing realistic DCR figures being quoted from manufacturer really, not made up numbers which don't translate into real performance. I'd rather see a screen with a useable DCR of ~10,000:1 for example than a screen with an advertised 20 million:1 which only works in the most extreme and unrealistic circumstances that a user will never see. In the case of the VP2770-LED the DCR works quite well, up to ~2823:1 for those who might want to use it.

Viewing Angles

Above: Viewing angles shown from front and side, and  from above and below. Click for larger image

Viewing angles of the ViewSonic VP2770-LED are very good and very similar really to an IPS panel, and what you'd expect from a PLS technology screen. Horizontally there are very wide fields of view with a small contrast shift only really becoming noticeable from a wide angle of about 45� and beyond. Vertically, the contrast and gamma shift was a little more pronounced but the fields of view were still good. The panel is free from the off-centre contrast shift which you see from VA matrices as well which is good news, and part of the reason why IPS was always a primary choice for colour critical work. PLS is now starting to become a popular alternative thanks to its very wide viewing angles. The PLS panel is also free of the very noticeable contrast and colour tone shifts you see from TN Film panels vertically.

Above: View of an all black screen from the side. Click for larger version

On a black image, like many IPS panels, there is a white glow when viewed from an angle. This picture was taken in a darkened room though and in normal working conditions this shouldn't present much problem. There is no A-TW polarizer or equivalent film on this panel which was something rarely used in the IPS market, but was implemented on some older IPS screens to improve the off centre black viewing. Because of the size of the screen you may notice some of this glow from the corners when you are viewing it head on. This is only really noticeable in darkened room conditions and when viewing dark content and is quite similar to IPS panels.

Panel Uniformity

Measurements of the screens luminance were taken at 35 points across the panel on a pure white background. The measurements were taken using BasICColor's calibration software package, combined with the NEC customised X-rite i1 Display 2 colorimeter. The above uniformity diagram shows the difference, as a percentage, between the luminance recorded at each point on the screen, as compared with the reference point of a calibrated 120 cd/m². This is the desired level of luminance for an LCD screen in normal lighting conditions, and  the below shows the variance in the luminance across the screen compared with this point. It is worth noting that panel uniformity can vary from one screen to another, and can depend on manufacturing lines, screen transport and other local factors. This is only a guide of the uniformity of the sample screen we have for review.

Uniformity of Luminance

The luminance uniformity of the VP2770-LED was a little variable. The central areas of the screen remained quite uniform, but the luminance dropped off towards the right and left hand edges. The luminance ranged down to 101 cd/m² minimum along these edges which represented a deviance of ~21%. Approximately 60% of the screen was within 10% deviance of the central luminance. There was nothing too severe here, but it was a shame the sides were not a little closer to the central luminance.

Backlight Leakage

Above: All black screen in a darkened room. Click for larger version

As usual we also tested the screen with an all black image and in a darkened room. A camera was used to capture the result. There was no severe leaking here, but the camera did pick out some clouding in the top right and bottom left hand corners. Along the top edge there was also a small amount of leakage. Overall nothing too bad but not a perfect backlight distribution.

General and Office Applications

The VP2770-LED features a massive 2560 x 1440 WQHD resolution which is only just a little bit less vertically than a 30" screen and becoming very widely used now in recent screens. The pixel pitch of 0.233mm is very small as a result, and by comparison a standard 16:10 format 24" model has a pixel pitch of 0.270mm and a 30" model has 0.250mm. These ultra-high res 27" models offer the tightest pixel pitch and therefore the smallest text as well. I don't find it too small personally, but day to day I am used to using resolutions of this size day to day. Some users may find the small text a little too small to read comfortably, and I'd advise caution if you are coming from a 19" or 22" screen for instance where the pixel pitch and text are much larger. I found a 27" screen to be quite a change with text size when I first used one but once you get used to it, it's hard to go back to a smaller desktop resolution.

The massive resolution is really good for office and general use, giving you a really big screen area to work with. It is a noticeable upgrade from a 24" 1920 x 1200 / 1920 x 1080 resolution, and it's good to see ViewSonic have opted to go with the high res panel here rather than reverting to a 1920 x 1200 or 1920 x 1080 res panel as you may find in other lower cost 27" models. More 1920 x 1080 27" IPS based models are starting to appear in the market now, but the added resolution of a screen like this is really beneficial. For those wanting a high resolution for CAD, design, photo work etc, this is a really good option. The image was very sharp and crisp and text was very clear. The light AG screen coating used on the PLS panel ensured that the white backgrounds of office documents looked good, and did not suffer from the overly grainy and dirty feel of some competing IPS panels featuring heavy, aggressive AG coating. It also remained free from the reflections you might experience from a full glossy solution so seems to be a good half-way between the two.

There was no defined 'text' or 'internet' preset mode available so you would have to set up one of the other preset modes to your liking for office work, perhaps even saving one using the user configurable modes in the OSD. Out of the box, the 100% default brightness is too bright for office use and measured at around 300 cd/m² in our tests. A setting of around 15% should return you a luminance close to 120 cd/m² for office use if you want, and you are able to control the brightness down to around 81 cd/m² at the 0% setting which is reasonable. Those wanting to use the screen in low lighting conditions shouldn't have much of any issue here. If you really want to be able to reduce the luminance further then the two other ECO mode settings will restrict the luminance range significantly, allowing you to reach down to ~10 cd/m² if you really want to. Be warned though, that is at the sacrifice of contrast ratio if you do use those modes. They also carry energy saving benefits as well if that is important to you. Another thing to note while we are talking about the brightness control is that the screen does not use Pulse-Width modulation (PWM) to control backlight dimming and so those who suffer from eye fatigue or headaches associated with flickering backlights need not worry here.

The screen comes with ViewSonic's 'SuperClear' engine which according to ViewSonic is a special firmware for helping to make the image details and resolution even more refined. It will be also included in other future IPS (and PLS) based models featuring the SuperClear name. Perhaps a "feature" of this SuperClear engine was the initial sharpness of the screen. There is a setting available within the OSD menu to control sharpness which is set at a default of 50 out of the box. We actually found this was a little too high and produced a somewhat unrealistic image. You may see similar features on other screens as well where certain presets accentuate the sharpness, producing a more unnatural feel, perhaps ok for movies and games, but not so good for general office work. In fact we found that switching this setting down to 25 (it is available in steps of 25) produced a much better image for general office work, reverting to a "normal" sharpness as you would find on other screens.

The stand provided offers a great range of adjustments although most are pretty stiff to use. It's good to see a decent range of tilt, height, pivot and rotate adjustments available which should allow you to obtain a comfortable position for your office though. If you want to, you can wall or arm mount the screen as well using the VESA 100mm option. With DisplayPort and DL-DVI both supporting the full 2560 x 1440 resolution you should have a decent choice for your PC connectivity. Since the VGA input was not able to support the full resolution of the screen we did not compare the sharpness of the image between analogue and digital, but the digital picture quality was excellent (note we switched to sharpness setting of 25 for improved image clarity). There were 2x USB 3.0 and 2x USB 2.0 ports included on this screen, with 2 available on the right hand side for easy access. It was good to see the upgrade to USB version 3.0 here for two of them for the faster transfer rates, and handy to have the easy access ports on the side for connection of printers, scanners, cameras etc. There are no integrated speakers on this model or card readers. An audio output is provided for when you are using the HDMI or DisplayPort interfaces and audio is being sent to the screen as well over those connections.

 
Above: photo of text at 2560 x 1440 (top) and 1920 x 1080 (bottom)

The screen is designed to run at its native resolution of 2560 x 1440 and at 60Hz refresh rate. If you want to you can run it outside of this and let the image be scaled to fill the screen. At the native resolution text was very sharp and clear. We ran the screen at 1920 x 1080 which was the next step down, while still maintaining the screens 16:9 aspect ratio. Text was actually pretty good and was not blurred much. The screen is perfectly capable of being run at a lower 1920 x 1080 resolution if you wanted to, without too much degradation in the picture quality and sharpness. To give you more desktop real estate and maximum picture quality, the native resolution is of course recommended where possible.

Responsiveness and Gaming

The VP2770-LED is rated by ViewSonic with a rather modest on paper 12ms G2G response time. This implies the use of overdrive / response time compensation (RTC) technology, used to boost pixel transitions across grey to grey changes and improve responsiveness in practice and reduce ghosting and blurring. The panel being used is an Samsung LTM270DL02 PLS Panel and it is rated with a 12ms ISO (black > white > black transition) response time for reference.

Before we get in to the side by side screen comparisons I want to quickly talk about the 'response time' (overdrive) control available through the screens OSD menu as shown. It is available within the 'picture' section as shown above. This allows you to manually control the level of overdrive / RTC impulse being applied to the pixels, with options of standard, advanced and ultra fast being available. You may wish to read our specs section for some further information about overdrive / response time compensation.

The screen was tested using the chase test in PixPerAn, a good bit of software for trying to quantify differences in real terms responsiveness between monitors. As a reminder, a series of pictures are taken on the highest shutter speed and compared. The images above are the best case examples from the screen with the 'response time' setting at each level. Please forgive the slightly blurry image in ultra fast mode as we were having issues with our camera! In the 'standard' mode the responsiveness of the panel is actually still pretty good. There is no obvious ghosting to the naked eye although a reasonable degree of motion blur is detectable. When switching to the 'advanced' mode, this blur is reduced a bit and the moving image looks sharper and clearer. This setting is turning the overdrive impulse up of course and so pixel transitions are being sped up. This translates into a real life difference in perceived response times. We saw a very similar performance from the Samsung S27A850D and S27B970D in fact when we tested them, which use the same LTM270DL02 panel as the VP2770-LED.

The 'ultra fast' setting turns the overdrive impulse up again another notch. However, in this mode it is turned up a little too high and is poorly controlled. As a result a feint white halo is introduced behind the moving car and a more noticeable dark trail behind the moving speech bubble. Here the overdrive is causing the pixels to overshoot their required state and unfortunately introduce this distracting artefact. The 'advanced' setting seems to deliver a more balanced performance, free from these overshoot issues. We had seen similar stories from the two Samsung PLS screens as well. Despite the slower specified response time of 12ms G2G here, it behaves pretty similarly in practice to the Samsung models which are rated by Samsung at 5ms G2G, although perhaps slightly slower.
 

Display Comparisons

The screen was tested again using the chase test in PixPerAn for the display comparisons. As a reminder, a series of pictures are taken on the highest shutter speed and compared, with the best case example shown on the left, and worst case example on the right. This should only be used as a rough guide to comparative responsiveness but is handy for a direct comparison of the impact of this setting:

27" 12ms G2G Samsung PLS (Response Time = Advanced)

27" 5ms G2G Samsung PLS (Response Time = Faster)

27" 5ms G2G Samsung PLS (response time = faster)

27" 8ms G2G LG.Display AH-IPS

We have provided a comparison of the VP2770-LED first of all against three other popular 27" models, including the two previous screens we have tested using Samsung PLS panel technology. As you can see, the VP2770-LED performs quite comparably to the Samsung S27A850D and S27B970D in these tests, in each case we have selected the middle response time setting to return the optimum pixel performance. The higher settings on each model introduced unwanted RTC overshoot in the form of dark halos and trails, so this middle setting seemed to be the better option. There was a slightly more noticeable blur on the ViewSonic than on the two Samsung models as you can pick out from the above photos, but not by much in practice. We have also included the Dell U2713HM, utilising a modern AH-IPS panel and offering some very low levels of motion blur as well, a little ahead again of the VP2770-LED.

27" 12ms G2G Samsung PLS (Response Time = Advanced)

27" 6ms G2G LG.Display H-IPS

27" 6ms G2G LG.Display H-IPS

27" 6ms G2G LG.Display H-IPS

27" 12ms G2G LG.Display H-IPS
 

We have also included comparisons against some other popular 27" IPS based models above. The VP2770-LED actually performed pretty well by comparison, despite its position as a more professional use screen, and its modest quoted 12ms G2G response time specification. The Dell U2711 here is an example where the overdrive impulse is too aggressive and has resulted in a noticeable dark trail. The other 3 IPS models were free of any such overshoot, but showed more obvious motion blur in practice.

27" 12ms G2G Samsung PLS (Response Time = Advanced)

27" 6ms G2G AU Optronics AMVA (SmartResponse = Fastest)

27" 8ms G2G AU Optronics AMVA (AMA setting = Premium)

27" 4ms G2G AU Optronics AMVA (AMA = Premium)

If you then compare the VP2770-LED with 3 other 27" screens we have tested which use AMVA panel technology there are more pronounced differences. The Philips 273E3QHSB and BenQ EW2730V fell behind in these tests. The generation of AMVA panel being used in those two models was not able to compete with the responsiveness of modern IPS or PLS displays and there were high levels of blur evident, even with their response time controls turned up to the optimum levels. Those screens are rated with a 6ms and 8ms G2G response time respectively which just goes to show you can't always trust a specification when determining real life performance of a display. The recently tested BenQ GW2750HM had offered some improvements and showed lower levels of blur. However, it was again not quite as fast as the VP2700-LED's PLS panel in practice though.

27" 12ms G2G Samsung PLS (Response Time = Advanced)

24" 6ms G2G LG.Display e-IPS (Video OverDrive = On)

24" 8ms G2G LG.Display e-IPS

23" 8ms G2G LG.Display e-IPS (W-LED)

24" 4ms G2G AU Optronics AMVA (AMA = Premium)

Above is a comparison of the VP2770-LED against some popular models in smaller sizes. First are three models using IPS panels, but in smaller sizes of 24" and 23". The HP ZR2440w had performed very well in these tests and showed slightly lower levels of blur, but a slightly more apparent overshoot in the form of a dark trail. The 24" Dell U2412M and 23" U2312HM again offered low levels of motion blur but a more obvious dark overshoot trail was introduced. I have also included the results from our recent review of the 24" BenQ GW2450HM since there had been some big improvements made in AMVA panel technology in this most recent generation of panel. Thankfully the responsiveness was much better than we'd seen from the Philips 273E3QHSB and BenQ EW2730V we showed you above and was on par in practice with these IPS/PLS screens.

27" 12ms G2G Samsung PLS (Response Time = Advanced)

24" 2ms G2G AU Optronics TN Film + 120Hz (AMA = On)

27" 1ms G2G Chi Mei Innolux TN Film + 120Hz (Over Drive = 0)

22" 3ms G2G Samsung TN Film + 120Hz

I've also included a comparison above against three very fast 120Hz compatible screens we have tested. In all cases these other screens are using TN Film panels and are aimed primarily at gamers. Firstly there is a direct comparison against BenQ's XL2420T. This showed very low levels of motion blur, but some dark overshoot was introduced as a side-effect. The recently tested Iiyama G2773HS was very responsive and even has a quoted 1ms G2G response time. This showed very low levels of blur and had minimal issue with overshoot. The Samsung SM2233RZ performed very well in these tests and showed very low levels of motion blur. When 120Hz mode was enabled the overdrive artefacts evident in 60Hz mode were almost completely eliminated, which is something we have seen here with the BenQ XL2420T as well.

There is something else going on here though as well which can't be picked out by the camera. All of these TN Film models are running at 120Hz refresh rates, which allows for improved 120fps frame rates and the support of 3D stereoscopic content as well. This can really help improve smoothness and the overall gaming experience so these screens still have the edge when it comes to fast gaming. From a pixel response point of view the VP2770-LED performed pretty well, but there are some other areas you still need to think about when it comes to high end gaming. It couldn't keep up with the very fast TN Film models with 120Hz support.

The responsiveness of the VP2770-LED was good and we were pleased by what we saw. It was very similar to what we'd seen from the other PLS panels in the past, but slightly slower perhaps due to the overdrive impulse being applied. The screen still showed low levels of motion blur and it was only if switching the overdrive setting up to 'ultra fast' that some overshoot was introduced. The 'advanced' setting is preferred to avoid such issues. The screen should be capable of handling a fair amount of gaming, even some fast paced games, although you may want to consider the type of graphics card required to run games with high settings at such a high resolution.

Additional Gaming Features

Aspect Ratio Control - The screen offers two options within the OSD menu for hardware level aspect ratio control. You can select full screen which will stretch the input aspect ratio and resolution to fill the screen completely. Or you can select 4:3 to maintain a 4:3 aspect ratio (or indeed force a 4:3 aspect ratio no matter what the input resolution is). These options are a little limited really, and there's no option to automatically detect and maintain the input aspect ratio. There is also no option for other possible aspect ratios such as 16:10 or 5:4 and no defined 1:1 pixel mapping option. This might not be a problem for PC gaming, where you can probably control the aspect ratio from the graphics card as well. It is also probably not an issue for many external devices as the native aspect ratio of the screen is 16:9 anyway. However, anything else might prove problematic if you had other non 16:9 aspect ratio inputs without their own aspect ratio control.

Preset Modes - There is no 'game' preset mode available from within the preset mode menu and so you will have to set up one of the other modes to your liking. You can of course then save it as one of the customisable user modes accessible through the quick launch 'up' arrow.

Input Lag

We have recently written an in depth article about input lag and the various measurement techniques which are used to evaluate this aspect of a display. We have also improved our method by adopting the SMTT 2 (now version 2.5.1) tool which is used to generate the results below. Please see our full input lag testing article for all the details.

For the full reviews of the models compared here and the dates they were written (and when screens were approximately released to the market), please see our full reviews index.

Our tests here are based on the new format using SMTT 2.0. We have provided a comparison above against other models we have tested to give an indication between screens. We have only included screens which were tested using this new method to allow for a fair and realistic comparison, and have removed any models tested using the old method.

The ViewSonic VP2770-LED shows a moderate level of input lag, just over 1.5 frame in delay on average. This was measured at 26.2ms average. Note that this is the overall display lag, and so accounts for the signal processing time + an element of the pixel response time. We have measured this with the response time setting turned up to its highest setting to minimise the impact of pixel response time as best we can. The lag of this screen has been categorised as CLASS 2 as detailed above. As such it may not be quite as suitable as other models for very high end gaming or fast first person shooters, but then again, this isn't really a gamer-orientated screen anyway.
 

Movies and Video

 The following summarises the screens performance in video applications:

• 27" screen size makes it a pretty good option for an all-in-one multimedia screen and comparable to smaller LCD TV's in size. A screen this big really does help lend itself to video viewing.

• 16:9 aspect ratio is more suited to videos than a 16:10 format screen, as it leaves smaller borders on DVD's and wide screen content.

• Native 2560 x 1440 resolution can easily support true 1080 HD content (1920 x 1080 resolution)

• Digital DL-DVI, DisplayPort and HDMI interfaces support HDCP for any encrypted and protected content

• Good to see DisplayPort and HDMI provided for connection of additional devices, both of which are very popular for external DVD and Blu-ray players.

• Light AG coating helps to ensure image quality is retained and not overly grainy, while also offering anti reflective properties which are useful for movie viewing, especially with lamps etc coming in to play in darkened room conditions. This is more suited to movie viewing than a full glossy coating.

• Contrast ratio was moderate for an IPS panel, but still sufficient to ensure detail in darker scenes and shadow detail should not be lost.

• Dynamic contrast ratio is available and works to a reasonable level, up to about 2823:1 in practice. You have to have a 100% black screen for it to function at a higher level which is probably never going to happen in real use.

• There is no specific 'movie' preset mode available in the OSD preset mode menu so you may want to set up another mode specifically for your movie viewing

• Good pixel responsiveness for movies and video which should be able to handle fast moving scenes without issue.

• Wide viewing angles thanks to PLS panel technology meaning several people could view the screen at once comfortable and from a whole host of different angles. The PLS glow from an angle might present a problem on darker content depending on your line or sight and distance from the screen

• Very good ergonomic adjustments available from the stand with full range of tilt, height and pivot being useful for obtaining a comfortable viewing position. They are pretty stiff to operate so you might not want to move the screen around too often.

• No severe backlight leakage from the edges which is good. This type of leakage may prove an issue when watching movies where black borders are present but it is not a problem here. Some slight clouding in the corners which might become evident in darkened room conditions sometimes.

• There are no integrated speakers available on this model although an audio connection is provided to connect headphones, taking the sound from HDMI or DisplayPort inputs if you are using them.

• No picture in picture (PiP) or picture by picture (PbP) modes available on this model.

Conclusion

The ViewSonic VP2770-LED proved an interesting alternative to some of the more mainstream models from Dell and Samsung we'd seen in recent months. It's been a while since we're seen a VP series screen from ViewSonic and this new 27" offering proved a good addition to the range. It retained much of the style and design of previous VP models and to be honest we felt it was perhaps a little blocky and chunky, and not keeping up with some of the slim and super-sleek models out there in the market. It did feel sturdy and well built, but somewhat industrial in design. unfortunately while the stand offered a very decent range of adjustments, the mechanics of these were not great and they were too stiff to move comfortably. At least they are included so you can obtain a comfortable position for different uses, but you wouldn't want to move it around too much. The range of connections and extras was very good though and it was good to see the addition of the latest USB 3.0 technology as well.

From a performance point of view it is an interesting choice for ViewSonic to opt for a Samsung PLS panel over an LG.Display IPS panel, despite what some of the marketing material might lead you to believe. The default setup was excellent, both in the factory calibrated sRGB mode and the native mode. This should bring a high level of accuracy to those wanting to do colour critical work on the screen even without a calibration device. The only odd thing from a colour rendering point of view was the support of an sRGB colour space. The native gamut is a little too wide for sRGB, and the sRGB emulation attempts in other preset modes fell a little short, not quite matching the colour space as accurately as you would hope. The screens performance was very comparable to what we'd seen from other PLS based screens in other areas, including a decent response time, moderate contrast ratios and wide viewing angles. It was a bonus that the screen did not use PWM for backlight dimming as well, and the screens AG coating remained at a light level as we had hoped. The contrast ratio was not as good as some decent IPS models but was on par with other PLS screens we have seen so far. The backlight uniformity on our review sample was not too bad either, but may of course vary from one unit to another.

The VP2770-LED retails in the UK at the moment for ~�620 GBP which puts it a little more expensive than popular 27" 2560 x 1440 resolution models like the Dell U2713HM (~�575) and the Samsung S27A850D (~�575). The screen has only just been released so expect that price to drop a little perhaps once it becomes more readily available, probably to a similar level as the Dell and Samsung offerings. It is a fair bit cheaper than some other professional grade screens like the Samsung S27B970D (~�800) and NEC PA271W (~�900) for instance. However, while the VP2770-LED is part of ViewSonic's "professional" VP line up, it lacks some of the high end features of a true professional grade screen with hardware calibration and uniformity correction technologies for instance. It does carry a great factory calibration, support for "10-bit" colour depth and a decent performance from its PLS panel though which would probably place it in a similar category with the Dell U2713HM and Samsung S27A850D. It's an interesting alternative and worth consideration.