Results: Stock Brightness And Contrast
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.