Original Link: https://www.anandtech.com/show/5752/nec-pa271w-when-accuracy-and-consistancy-matter



NEC PA271W - Design and Specifications

As long as I’ve been following, using, or writing about computers, NEC has been a leader in displays. From the early MultiSync monitors to their current line of LCDs, they have been focused more on pushing performance than on dropping price, which has kept many of us from owning one of their displays. Of course, there is a large swath of users that always want to have the best, and are willing to pay for it.

Back with a CRT, this was pretty easy to do. We didn’t have to worry about lag, we could run multiple resolutions on a display natively, and if a display supported higher resolutions, faster refresh rates, and better sharpness, it was likely going to work for most power users. Now the field is a little different, as you have to worry about the native resolution of your panel, the response time, viewing angles, color quality, and more. All of this has led to a marketplace with different solutions for different needs than before where a "one-size-fits-all" approach doesn't really exist anymore.

Virtually every 27” 2560x1440 IPS display out there currently uses a panel from LG as its starting point. From there your choices can be from CCFL or LED backlights, sRGB or AdobeRGB color gamuts, and the electronics you wish to engineer behind the panel. It is in the panel electronics and settings that NEC adds their own engineering to set their displays apart from the rest.

When you take it out of the box, you’ll notice that the PA271W is very large and almost overbuilt. Where many lower end, consumer focused panels are engaged in a race to how thin they can be, the NEC is a sizable display that is fairly heavy and takes up a large amount of space. One reason for the large size is the presence of a custom designed cooling system for the CCFL backlight. As the monitor warms up and the lamp comes up to its full operating temperature, it can cause color shifts across the panel. NEC is aware of this and has made the display as large as necessary to deal with this issue.

To further deal with color shifts across the panel, NEC has a display uniformity option that lets you sacrifice maximum brightness for a smaller shift across the panel. Each panel is individually measured and calibrated at the factory for this feature, so that if you are looking at a solid white screen it should remain white across the whole screen, free of any shifts to red, green, or blue. There is also a pair of upstream USB connectors instead of the usual one, which allows the NEC to function as a KVM switch as you move between inputs.

The OSD in the NEC is full of all the information you could want to know, from the current colorspace and brightness to how much power you have used since you installed the display. The menu system works well, with labels for all the controls that appear on the screen when you pop it up. It does a good job of not changing how different buttons interact with the menu on different screens, which is what makes some OSD systems a pain to navigate, but it does spread the buttons out a bit which makes it harder to navigate than those from Dell. Overall the OSD is well done.

Of course with an IPS panel you expect good viewing angles, and the NEC doesn’t disappoint here. If you get to extreme viewing angles you can start to see a bit of a shift, but it’s impossible to do any work with an angle like that so I wouldn’t consider it an issue at all.

NEC PA271W
Video Inputs 1x DisplayPort, 2x DVI-DL
Panel Type IPS (8-bit native, 10-bit with A-FRC)
Pixel Pitch 0.23mm
Colors 1.07 Billion
Brightness 300 nits
Contrast Ratio 1000:1
Response Time 7ms
Viewable Size 27"
Resolution 2560x1440
Viewing Angle 178/178 Horizontal/Vertical Degrees
Backlight CCFL
Power Consumption (operation) 117W
Power Consumption (standby) 1.4W
Screen Treatment Anti-Glare
Height-Adjustable Yes
Tilt Yes
Pivot Yes
Swivel Yes
VESA Wall Mounting Yes, 100x100mm or 100x200mm
Dimensions w/ Base (WxHxD) 25.2 x 15.6-21.5 x 9.3 in.
Weight 30 lbs
Additional Features 2 USB Up, 2 USB Down, 14-bit LUT
Limited Warranty 4 years
Accessories DisplayPort cable, USB Cable, DVI Cable, Power Cord. Optional SpectraView calibration package.
Price $1098 + shipping online (as of May 1, 2012)



NEC PA271W - MultiProfiler and SpectraView

Included in the box was NECs MultiProfiler software, and they also provided their SpectraView II calibration software for this review. With MultiProfiler you can set up five preset modes on the PA271W, allowing you to quickly switch between settings based on content, lighting conditions, or even computer. As an example, I could assign positions 1 and 2 to use the sRGB gamut, with brightness settings of 200 nits and 100 nits. Then for photo editing I could do the same with positions 3 and 4, only with the AdobeRGB gamut instead. Finally I can use position 5 for my profile that I calibrated with the SpectraView software and using the full native gamut of the display.

While for most users you might consider this level to be overkill, it isn’t for the professionals targeted by NEC. If you are a video editor, you can quickly switch between Rec 709 (HDTV), SMPTE-C, and DCI color gamuts to work on mastering in each of the different colorspaces. If you want to create a custom profile that mimics your print material more closely you can do that as well, allowing you to quickly change between editing for screen and print. I know this won’t matter to 95% of readers, but for those that need to quickly switch the feature proves very valuable.

As I mentioned before there are multiple USB upstream ports in the PA271W, and in MultiProfiler you can configure these to work as a KVM switch depending on input. I connected my keyboard and mouse to the USB ports on the NEC, then I connected one USB upstream port to my PC and one to my MacBook Air, and I connected each PC to a different video input. Using the software I could set the upstream USB ports to be tied to different display inputs, so as I changed the display between the two computers, the devices changed as well. This worked well during testing when I wanted to use different meters in both Windows and OSX for calibration, as they could be hooked up to the display and then automatically switch computers as I switched inputs.

MultiProfiler also includes support for things I hadn’t seen before, such as adjusting the color output to mimic different types of color-blindness, so designers can make sure their content will work for everyone. Finally, you can also configure a PIP setup as well.

SpectraView II is NECs updated calibration software designed for their displays. Available with or without a meter (they sell an OEM version of the i1Display Pro, which is a large improvement over the previous i1Display2), the monitor and software interface directly with your meter and then calibrate the 14-bit internal LUTs while also generating the ICC profile for your OS.

Within the software you can specify your targets and save them to come back and redo the calibration later. With this I was able to set up our targets: 100 nits, D65 for white, 2.2 for gamma, and then try it for sRGB, AdobeRGB, and Native colorspaces. The software uses DDC to communicate with the monitor and will even give you a warning if it’s been on for less than 30 minutes before calibration, as it is still warming up and colors could shift until it is fully warm.

Creating profiles was quick and easy, with support for both my i1Display Pro and i1Pro, which I wound up using for these. Once you perform a calibration you are given the results with contrast ratio, dE for the grayscale, how close you are to the RGB targets, and the gamma curve. Due to its ability to adjust the LUTs in the monitor directly, I’d imagine most people considering the NEC would also be buying a copy of SpectraView II to calibrate it, as I would.



NEC PA271W - Brightness and Contrast

The NEC is rated fairly conservatively at only 300 nits of light output at maximum, though for a professional work environment that is likely more than anyone would need. The OSD for the NEC lets you know the light output in cd/m^2 (which is equivalent to nits) as you raise and lower the value, and once you move past 250, the color changes to let you know you’re going beyond where the screen uniformity measurements can help you. Driven to the maximum output, the screen might read 400 cd/m^2 but the actual value was far less than that.

White Level -  XR Pro, Xrite i1D2 and XR i1DPro

As we can see, we managed right around the maximum value of 300 nits, so that conservative estimate is right on in this case. The OSD might not indicate the correct value once you move past the recommended 250 cd/m^2 level, but below that it seemed to be within 3-4% of the listed value which was pretty good. You can see the lowest light output level was down to 57 nits, which means you can adjust the display to be dim enough for any work environment you might have.

Of course, with our accurate white levels we have to hope that we get good black levels as well, which has not been the high point for IPS screens with CCFL backlights, as opposed to LED dimming setups, in the past.

Black Level - XR Pro, Xrite i1D2 and XR i1DPro

Unfortunately our black levels do leave a bit to be desired. The level at the minimum is 0.119, and I’d hope for something closer to 0.050 or less, and the maximum level was 0.429, which looks closer to a dark gray than black at that level. These indicate that our contrast ratio probably is going to leave a bit to be desired with the NEC.

Contrast Ratio -  XR Pro, Xrite i1D2 and XR i1DPro

As we could guess, the contrast ratio with the minimum backlight is only 480:1, and it rises up to 762:1 with the monitor at maximum output. With the wide swing between these two values I went ahead and measured the contrast ratio at our calibrated 200 nits setting and found it was 561:1, so the ratio improves as the light output level increases. It seems there is a minimum amount of light that the IPS panel is going to let through, which could be related to the screen uniformity technology used by NEC on the display, but you should be aware that if you want deep, dark blacks you’ll need to look for a different display using either a different panel technology, a different backlighting technology, or both.



NEC PA271W - Color Quality and Color Gamut

Targeted directly at designers and other graphics professionals, we’d expect to see excellent performance, hopefully before and after calibration from the NEC. For the initial measurements, with so many options available, I used the included ICC profile and set the monitor to sRGB mode as well as 200 nits of light output.

Color Tracking -  XR Pro, Xrite i1D2 and XR i1DPro

Pre-calibration we get an error of 7.07, which is a bit higher than I thought it would be, with a really high error in the grayscale. Overall this was OK, but I highly doubt many people will buy this display without choosing to calibrate it given its target market. Our target settings were a 2.2 gamma, D65 white point, and 200 nits of light output. ColorEyes Display Pro doesn’t give a color gamut option, so I assume it is targeting the native gamut of the display.

Color Tracking -  XR Pro, Xrite i1D2 and XR i1DPro

Color Tracking -  XR Pro, Xrite i1D2 and XR i1DPro

This is much better after a calibration, with an average dE of only 1.51 and a median dE of just under 1.1. You’ll notice the last color sample before pure white, a turquoise blue, has a much lower error here than on most displays. This is the shade of blue that actually lies outside of the sRGB colorspace and so most displays cannot reproduce it, leading to a very high dE there. The only panel to do better recently is the 30” NEC that has a true 10-bit panel.

Color Tracking -  XR Pro, Xrite i1D2 and XR i1DPro

As the print market is a main area for NEC to target with this display, its performance with 100 nits of light output is of more importance than usual. Here we find that the NEC performs almost identically to its 200 nits results, which is actually quite good. As many displays get better or worse as the light output changes, that indicates they will only perform at their best at a certain light level, whereas if you are consistent the user can set the light to match their environment. The NEC doesn’t run away from the competition in any of these tests, but it performs very well, and very consistently.

You won't be lacking for gamut here either, as the NEC covers over 109% of the AdobeRGB gamut, meaning that for any work you are doing, even including something like DCI Cinema, the NEC has you covered.

LCD Color Quality



NEC PA271W - Display Uniformity

As we’ve mentioned, NEC goes to great lengths with their PA271W display to make it as uniform as possible. With the sacrifices in maximum light output we hope that we will see a measurable difference on the NEC in both brightness and color uniformity.

The brightness uniformity chart shows results that are far and away the best I have measured to date. The total deviation from the maximum to the minimum value is only 10 nits, and we are used to seeing a swing of 30 or even more nits on this test. The average deviation is only 1.66%, so this is a really fantastic result showing that NEC has managed to engineer a more uniformly bright panel than anyone else.

Measuring the black uniformity is harder, as we have no 200 nits target that the white uniformity has. In this case we wind up with an average black level of 0.35 nits, but a higher standard deviation of 18.7%. The issues fall in the upper-right area of the screen which also had the brightest areas in the white uniformity testing, so there might be a little more light leakage coming in from that area of the panel it seems. Note that this non-uniformity will likely vary by panel as well. Given that the panel is uniformly lit, and that affects the color accuracy to a great deal, I would expect the panel to have a fairly consistent dE across the display.

LCD Color Uniformity

The NEC delivers here again. We wind up with average and median dE values of 1.84 and 1.81, and a standard deviation of only 0.27 dE. The upper right corner seems to have a bit of an issue again, likely due to that lighting uniformity issue, but the rest of the panel is remarkably close together. The colors are all uniform in error across the screen and the issue seems to be a slight rise in grayscale error as you move away from the center. Compared to any other panel I have reviewed, the NEC is far more uniform and will exhibit less of a color shift across the unit, which is important on a screen this size. It still isn’t perfect by any means, but it’s better than anything else I have tested.

I also realized with this review that the vertical axis here was shifting between each review, so I’m going to keep this at 8 for this review, and then see going forward if that is correct. This will make it easier to compare across different displays.



NEC PA271W - Input Lag and Power Use

The last 27” display I tested, the HP ZR2740w, was a pleasant surprise for gaming as it had a very low lag time despite the IPS panel and high resolution, likely due to the lack of an internal scaler or LUT to add a delay. Since the NEC has a scaler, and the additional custom electronics to provide display uniformity, I wasn’t certain that the NEC would perform as well.

Processing Lag Comparison (By FPS)

As you can see, the NEC is not going to be a display for a serious gamer, though it really isn’t targeting that market either. The input lag was 20.5 ms, and the pixel response took 24.9 ms to go from blue to yellow to blue, giving us an overall response time of 32.95 ms. The effective (subjective) lag was a little better, but with that high input lag it was still close to 25 ms, which is more than most serious gamers would be interested in. If you want a 27”, 2560x1440 resolution display for gaming the HP is still your best option.

The PA271W has a built in power use monitor showing you how much power you are using with the display, so being efficient is something that it does aim to do. With the backlight set at minimum we used 51 watts, and at maximum we used 119 watts. These were both worse than the HP as well, but since the HP uses an LED lighting system we would expect it to come in behind. Since the LED lighting system provided for a smaller gamut than the NEC's CCFL system produced, and a less uniform screen, I’m certain that had something to do with NEC's decision to stay with the CCFL technology on this panel. Power use wasn’t bad, it just wasn’t exceptional, and any 27” display is going to use far more power than a 24” or smaller one.

LCD Power Draw (Kill-A-Watt)



Conclusion: Targeting Professionals

Sometimes it is very easy to write a conclusion on a product that is at a premium price point. If Intel or AMD come out with a CPU that’s faster than anything else out there, you can easily say “If you need the performance, or can afford it without an issue, just buy it.” With the NEC PA271W, despite the premium price it carries, the answer really isn’t quite as straight forward.

The easiest answer is for those who are gamers. The only 27” monitor with 2560x1440 resolution I can recommend is the HP ZR2740w. Every other 27" QHD monitor tested has had far worse lag, well more than a frame, and you just aren’t going to be happy with it. Perhaps if we see a move towards 120Hz panels at this resolution this will start to improve, but the target still seems to be graphics professionals at this point, not gamers.

If you are a design professional who needs accurate color more than anything else, and things like display uniformity and a wider gamut are of high importance, then you are the target for the NEC. You already know you might need this, which features you can’t live without, and are willing to pay the extra price. Of course you might have already bought one, or you got to a point in the article that you realized you needed one.

So what’s left is the power user that wants premium performance but doesn’t require it for their job, who wants to know if it’s worth it. Many of the features, like the KVM ability and the multiple presets, I found myself using a good deal at the desk. If it was bright I can easily switch to a higher output mode, and if it’s dark I can switch back to the lower setting. Switching between sRGB and AdobeRGB is nice for editing images as well, since I use my SLR in AdobeRGB mode. However, when you can buy two of the HP 27” displays for around the same price as a single NEC, are those features worth it?

Personally, I’m not certain I can justify the extra cost. I like having a highly accurate display, but the HP performed well after calibration, even though it wasn’t nearly as uniform. The extra features like a color-blindness mode might be essential for a designer, but for even a power user they likely will never get used at all. In the end I find myself saying that I really loved working on the NEC, and would love to own one, but for my use I can’t see spending the extra hundreds of dollars over the HP to get features that aren’t essential to me or my work. For some people they will be, but for most people there are monitors that might lack that last bit of performance but will get the job done just as well.

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