HP z27x Review
by Chris Heinonen on December 2, 2014 4:00 PM ESTSurprisingly the HP z27x does not fare well on our uniformity testing. With most professional displays, having good uniformity is important because of their target market. This makes the performance that we see from the HP z27x all the stranger.
White Uniformity sees a lot of light drop-off at the edges of the screen. A very good display will only drop down 10% to 180 cd/m2 or so but the HP falls all the way to 153 cd/m2 in one zone. This fall-off of almost 25% is much higher than would be expected, and is something you can see when you have a uniform field up on the screen.
Black Uniformity is similar, with those same zones on the display having a lot of light fall-off leading to darker blacks. Having darker blacks is always good, but these are dark because of uneven backlighting which is not something we want to see of course.
The contrast uniformity shows that these backlighting issues are pretty consistent. There is some variation in the contrast ratio, but the minimum level is 900:1 and it goes up to 1,047:1 in one zone. This is better than we measured with the APL patterns (uniformity uses full-field) and everywhere on the display has a good contrast ratio. The contrast uniformity measures very well on the HP z27x.
The biggest issue is the color uniformity. This is probably tied back into the white uniformity, as the luminance level being incorrect will cause the colors to be incorrect. One zone, the very dim one, has an average dE2000 of almost 6.0 compared to the center. This poor backlighting causes the colors to all appear off compared to what is in the center. The panel itself might be uniform but if the backlight is not, what you see on the screen will not match up.
Overall the uniformity measurements of the HP z27x surprise me. I expected much better results from the monitor because of its target market. The panel might calibrate to be very accurate, but what you see in the center of the screen is not going to match up to what you see on the edges of it.
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bobbozzo - Tuesday, December 2, 2014 - link
Hi,It wasn't clear to me which is preferred - using (renting?) a Klein K-10A colorimeter and doing the self-calibration, or doing software calibration?
Thanks for the article
cheinonen - Tuesday, December 2, 2014 - link
Doing it inside the monitor is best, as you don't need to worry about the PC LUT being correct, it will just be accurate on any computer hooked up to it.Samus - Tuesday, December 2, 2014 - link
A worthy successor to my Dreamcolor LP2480, moar resolution and USB 3.0!Oubadah - Sunday, December 21, 2014 - link
Plus no A-TW Polarizer and inferior backlight array. This monitor isn't in the same class as the last gen Dreamcolor. Not to mention it's bugs and abysmal quality control. http://www.liftgammagain.com/forum/index.php?threa... I wouldn't touch this monitor with a barge pole at the moment.tyger11 - Tuesday, December 2, 2014 - link
When are we going to see monitors with HDMI 2.0 and DP 1.3?cheinonen - Tuesday, December 2, 2014 - link
Once we have chipsets. The issue with HDMI 2.0 is that all the current HDMI 2.0 chipsets with the full bandwidth don't have HDCP 2.2 as well. The HDCP 2.2 chipsets only use a subset of HDMI 2.0 and so they can't send as much data. Hopefully at CES next month we'll see products announced using new chipsets.wolrah - Wednesday, December 3, 2014 - link
Does HDCP actually matter to PC users? Aside from legitimate playback of Bluray/HD-DVD content what else on a PC ever gave a shit about it? I think iTunes did at one point, no idea if it still does.I mean there are technically roles a PC can fill for which it matters, but personally even among those I know who have BD-ROM drives in their PCs (a slim number, optical drives altogether are a dying breed) I don't know anyone who actually uses their PC to watch movies from disc. Anyone who uses discs uses a hardware player or more often a console, and anyone who uses a PC just sources from the internet in one way or another.
For TVs HDCP is a big deal, but for a computer monitor I'm finding it hard to care.
cheinonen - Wednesday, December 3, 2014 - link
I don't know that it's a big deal for straight PC usage, but it's also likely to upset people if they buy an HDMI 2.0 monitor, only to discover when they try to hook up their other 4K devices to it that they won't play back a 4K image. Since the chips are expected to be at CES, I don't think we will have to wait too long for them and IMO I'd rather have a display that can do that, without needing MST for a 60Hz refresh rate, than have a monitor today that will be out of date that fast.chaos215bar2 - Wednesday, December 3, 2014 - link
On a Mac, at least, iTunes most certainly still does care about HDCP. Even Netflix manages to check it when using the HTML5 player. HDCP may be silly, but it's still important if you want to watch videos on your computer without the hassle of stripping DRM.DanNeely - Thursday, December 4, 2014 - link
As of about 8 months ago (last time I tried using it) Amazon Instant Video also required HDCP for higher quality streams.