Brightness & Contrast
To read about our monitor tests in-depth, please check out Display Testing Explained: How We Test Monitors and TVs. Brightness and Contrast testing is covered on page two.
Acer XB280HK
NEC PA322UHD
Philips BDM4065UC
Uncalibrated – Maximum Backlight Level
Ultra HD monitors are available in several distinct flavors, 24 and 27-inch IPS, 28-inch TN and 32-inch IPS or IGZO. We’ve reviewed multiple examples of each so for today’s group we’re including NEC’s PA322UHD, ViewSonic’s VP2780-4K and V2475Smhl-4K, Acer’s XB280HK and the unique 40-inch Philips BDM4065UC, the lone VA example.
NEC claims a typical output of 350cd/m2 but it you need to light up the main street of a small town, the EA275UHD is up to the task. With over 470cd/m2, you can use this display outdoors on a location shoot even in bright sunlight. Luckily there’s plenty of range in the backlight to allow levels more appropriate for indoor use.
The super-bright backlight is the main reason for a high max black reading. Actual contrast is quite high as you’ll see in the next chart.
The Philips’ VA panel will likely crush the competition for some time to come. But the EA275UHD is the best of the rest. Only the best IPS panel can top 1100:1 and NEC has done that easily. This is one of the factors behind its clear and vivid image.
Uncalibrated – Minimum Backlight Level
NEC favors low minimum backlight output though this display doesn’t go as low as some of its others. The only drawback to this approach is that each click of the brightness slider represents at least 3-5cd/m2. That makes it a little harder to achieve a precise setting if you need it.
Of course a low black level is the natural result of a low minimum white value. It looks like the on/off contrast stays pretty consistent throughout the brightness range.
The EA275UHD retains its second-place position in the minimum contrast test. Aside from the Philips, this display has the best contrast of any Ultra HD screen we’ve tested plus it beats most IPS panels regardless of resolution.
After Calibration to 200cd/m2
Since we adjusted a color mode that started at 7500K, the RGB sliders required more tweaking than usual. This results in a hit to both black levels and overall contrast. Here you can also see the results of the uniformity compensation feature. It’s pretty subtle but it does raise the black level slightly.
Our calibration knocks around 19-percent off the max contrast value. And engaging uni-comp reduces it by a further 20-percent. Given the excellent results we recorded with the feature off, we recommend only using it when absolutely necessary. There are variations between samples of course but given NEC’s top-notch quality control it’s hard to image needing the compensation in most situations.
ANSI Contrast Ratio
ANSI contrast stays pretty close to the calibrated on/off value which is a very good thing. Turning on the uniformity compensation drops the figure by 12 percent; an amount that’s hard to see in a side-by-side comparison. Based on all our contrast and luminance tests we’d say the best mode is sRGB. It has nearly perfect grayscale response and decent color gamut accuracy. And it keeps the contrast level above 1100:1. Calibration doesn’t produce much gain unless you need even finer tolerances for color and white point.