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Results: Stock Brightness And Contrast

HP ZR2740w Versus Asus PB278Q: QHD 27" Monitors, Tested
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Before calibrating the two panels, we measure zero and 100 percent signals at both ends of the brightness control range. This shows us how contrast is affected at the extremes of a monitor's luminance capability.

Both screens are very bright, but the HP exceeds its own spec by almost 40 cd/m2. Fortunately, color and gamma are largely unaffected by maxing the brightness. So, should you actually need over 400 cd/m2 of light output, the ZR2740w can surely deliver. The Asus is near the top of the pack with over 286 cd/m2 available.

With so much output on tap from the HP, let’s see how black levels are affected.

Both panels are very well-engineered in that they can maintain a decent black level at maximum output. You can see how cranking the brightness affects the Auria’s black level more negatively than the other screens. The Samsung remains the undisputed leader in this test.

Topping out the brightness slider is usually not the way to achieve a good contrast ratio, since black levels rise right along with the peak number. Better-designed screens can buck this trend to some degree.

The HP ZR2740w comes within striking distance of the contrast-leading Samsung S27B970D. And the Asus PB278Q is not too far behind, either. For any panel to measure over 1,000:1 in native contrast is excellent performance. Even at max settings, both monitors deliver a nice, punchy image with plenty of depth and detail.

Not all monitors are practical for use at the minimum brightness setting. We consider 50 cd/m2 to be a realistic lower limit for viewing in a totally-darkened room.

Here, the Asus stays above the 50 cd/m2 mark, but the HP falls a good bit short. At 27 cd/m2, the ZR2740w’s picture is dim enough to cause eyestrain during extended use. A few clicks of the brightness button can bring the image to a usable level. This is made a bit more difficult thanks to the lack of an on-screen menu or even a level indicator. You have to set the level by eye, so it’s practically impossible to hit the same mark every time you make a change.

The fun part about bottoming out the brightness control is seeing how low the black level becomes. Even though it’s not completely realistic, some panels achieve absurdly low numbers.

The HP ZR2740w is the new king of the minimum black level test. In fact, we had to average several readings because we neared the limit of our spectrophotometer’s measurement capability. Just remember that the HP is too dim to be used for extended periods at these settings. The Asus and both ViewSonic monitors do produce a usable image at their respective minimum brightness settings, yet still manage to crank out a very low black level. If you increase the HP’s brightness to 50 cd/m2, the black level only rises to 0.0462 cd/m2, which is still excellent performance.

Along with low black levels come extremely high contrast ratios.

Once again, the HP nips at the Samsung’s heels at 3,346.2 to 1. The Asus takes up a firm position in the middle, with a very respectable 1,215.6 to 1.

No matter what the brightness setting, both monitors produce excellent contrast. You can use them at any light level you desire and still enjoy nice contrast, for an image with plenty of depth and pop.

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  • 0 Hide
    KOKing , May 16, 2013 10:24 PM
    I've had one of these HPs at work for a couple of months (replacing an early 24" 1920x1200 IPS), which I've set fairly low), but as this review says, it's not really necessary. I was a little disappointed that, possibly because of the aspect ratio change to 16:9, it doesn't _feel_ like a lot more screen real estate.
  • -8 Hide
    Immoral Medic , May 16, 2013 11:13 PM
    Add 120hz, THEN it's enthusiast level.
  • -2 Hide
    bit_user , May 16, 2013 11:18 PM
    Where are all the OLED monitors? They should be cheap and plentiful, by now!
  • 8 Hide
    cangelini , May 16, 2013 11:59 PM
    SIDDHARTH MISHRAUseless review, the uniformity on these screens is pathetic, tried three of each, the color temp difference across the screen is over 1000K. Toms has very poor reviewers, only prad.de and overclockers.ru do reliable screen reviews. And btw the U2713HM is regularly on sale for $500 or so, the ZR2740W is now an overpriced relic lacking even an OSD.

    Screen uniformity is covered on page eight, and low points on both screens are discussed.
  • 0 Hide
    flong777 , May 17, 2013 2:03 AM
    Am I right by saying that the Asus monitor has more accurate color and better grayscale performance.
  • 2 Hide
    Marcus52 , May 17, 2013 2:07 AM
    Surprised that the Asus has slightly better lag results, as one of the reasons for not having an OSD is to reduce lag, and it can make a big difference. Of course, how you measure lag can get different results, and I've seen much lower numbers for the ZR2740w:

    http://www.tftcentral.co.uk/reviews/hp_zr2740w_v2.htm

    tftcentral is showing the HP as having far less lag than the Asus panel.
  • 4 Hide
    ceberle , May 17, 2013 5:07 AM
    The Asus certainly calibrates better than the HP; mainly because it can be calibrated. The HP is slightly better out of the box for grayscale and its chromaticity is also a touch better. Both screens have identical color to the eye. Only the instruments can tell the difference.

    Christian
  • 5 Hide
    ceberle , May 17, 2013 5:12 AM
    Regarding the lag results: It's hard to compare numbers from one review to another when the testing methods are so different. With our high-speed camera procedure, the only fair comparison is between the monitors we've tested. I would defend our response test as definitive though. Actually watching the screen draw in slow motion leaves no room for interpretation. The lag test is also consistent since we use the same signal chain for every screen. There is never a change in video cards, drivers, peripherals or any other device that might affect the result.

    Christian
  • 3 Hide
    dgingeri , May 17, 2013 7:22 AM
    I have the HP ZR2740w, and have for over a year now. It's a great looking monitor, and it performas well by my standards, but suffers from a significant lack of both reliability and support. HP's support is massively fragmented. It took me over three hours on the phone to get to the department that actually handled the support for this monitor. (It is a "Commercial" monitor, not business or personal. It's splitting hairs mighty thin, but that's the way HP's support is separated out.) When I finally got through, they sent a tech with a replacement monitor the next day. However, it also has two major hardware issues that render it useless when they occur. Most of the first run monitors had the power supplies die within months. The second run monitors had a serious issue with the control boards. All of them have issues with the USB hub, but it least the monitor keeps working if you don't have the USB cable plugged in. As an owner of one, I would not, under any circumstances, recommend this monitor to anyone.

    HP: the perfect example of a company falling apart because it is both too big and too fragmented.
  • 0 Hide
    ubercake , May 17, 2013 8:42 AM
    Does anyone know how absolute input lag of the IPS monitors compares with that of higher end TN-panel monitors?
  • -1 Hide
    maxinexus , May 17, 2013 9:02 AM
    Who cares about 1440p...where are the 4k gee how long does it going to take!!!
  • 1 Hide
    sempifi99 , May 17, 2013 9:52 AM
    I have had this HP monitor for about 2 years now. It is a good and solid monitor. It turns on in a matter of seconds and the 12 ms response time is not a problem at all. Though I do wish it was a bit quicker, but you can not have everything at this price point. Also, there is software calibration to adjust the color output so the lack of monitor adjustment did not bother me at all.


    What I don't understand is the difference of input lag compared to other reviews. The Acer has been measured at 16.6 ms while the HP is an amazing 3.6 ms with a CRT being used as the zero set point. I am not sure the exact toms hardware testing methodology but it seems to synthetic, not representing real world performance.
  • 0 Hide
    ceberle , May 17, 2013 12:56 PM
    The testing procedure is explained in the review. We shoot video at 1000 fps of a black to white screen draw. Then we simply count the number of frames it takes for the white field to fill the screen. The input lag is measured the same way. The video shows the pattern generator's lights flashing when the signal is sent to the monitor. We count the frames between the flash and the full rendering of the pattern to arrive at the input lag measurement. We do this five times and average the results.
    -Christian
  • -1 Hide
    Nintendo Maniac 64 , May 17, 2013 1:35 PM
    So I guess I'm the only one interested in a monitor's upscaling quality? I mean, we don't always play the latest AAA games - I myself like to play some Touhou from time to time, but it's locked to a 640x480 window which is pretty tiny on a high-res display. That leaves you with fullscreen which puts you at the mercy of your monitor's and/or GPU's upscaling ability.
  • 0 Hide
    Anonymous , May 17, 2013 2:24 PM
    Hp when oh when are you going to make a 30 inch 2560 x 1600 led or oled display or better yet a 4K ready version at 30 inches or better??
  • 1 Hide
    Spooderman , May 17, 2013 5:17 PM
    Considering the cost of such a panel, probably not for the next 5 or so years.
    soldier2013Hp when oh when are you going to make a 30 inch 2560 x 1600 led or oled display or better yet a 4K ready version at 30 inches or better??

  • 0 Hide
    mczak1 , May 17, 2013 8:43 PM
    No workaround for other resolutions? Seriously? Last time I checked gpus had output scalers (since about 15 years or so...). Maybe you need to activate it manually if the driver can't figure out the monitor can do scaling on its own but pretty sure it should work...
  • 1 Hide
    agnickolov , May 17, 2013 10:54 PM
    Quote:
    With UHD (Ultra HD, 4K, or 2160p) just around the corner, QHD represents the highest pixel count that you can put on your desktop right now.

    Technically, there's also 2880x1800, but it's only on iMac-s so far. Still, the panels exist...
  • 0 Hide
    MasterMace , May 17, 2013 11:46 PM
    1440 and 1600p are now old. 2160p is where it's at :) 
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