Results: Brightness And Contrast
Uncalibrated
Before calibrating any panel, 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. We do not push the contrast control past the clipping point. While doing this would increase a monitor’s light output, the brightest signal levels would not be visible, resulting in crushed highlight detail. Our numbers show the maximum light level possible with no clipping of the signal.
Our comparison group for this review is the last six displays reviewed here at Tom’s Hardware.
The EA294WMi is a very bright monitor when all of its sensors are deactivated. You’ll need to turn off Eco Mode and Auto Brightness if you want to crank up the light output this high. While 343.4901 cd/m2 is quite bright, there are situations where it’s appropriate. For most environments, however, 200 cd/m2 is our recommended setting. This is the second-highest figure we’ve recorded this year. Only the HP ZR2740w is brighter.
At these settings, black level can often be high as well.
The NEC maintains a fairly low black level at maximum brightness. This is a well-engineered and well-built product; this is the sort of performance we expected at such a lofty price point. Overall, NEC's EA294WMi yields the third-best result among the monitors we’ve tested in 2013.
This bodes well for overall contrast in its stock configuration.
The EA294WMi takes second place in today's comparison and third for 2013. When you can turn up a monitor’s brightness control all the way and still get this kind of contrast, you have a very versatile screen able to deliver a nice punchy image in any lighting environment.
For the next group of measurements, we turn down the brightness control to its minimum setting and leave the contrast unchanged. The EA294WMi measures 6.7205 cd/m2, which is well below our minimum standard of 50 cd/m2. We recommend staying above that level to avoid eyestrain. The monitor is pretty much unusable at this setting. To hit our standard, we turn up the Brightness control to 11.
At a very low brightness setting, we often see amazing black level numbers.
Our measured result looks impressive on the chart. But remember, at just over 6 cd/m2, the image is far too dim, even in a completely dark room. Fortunately, the black level only rises to .041 cd/m2 when you set the monitor for 50 cd/m2 of maximum brightness.
Because of the low white level, the EA294WMi’s minimum contrast ratio is quite poor. Of course, you would never use the monitor configured as we're testing it. When you turn Brightness up to 11, the contrast ratio rises to a very respectable 1253.1 to 1. At that setting, the monitor looks fantastic with the lights out!
After Calibration
Since we consider 200 cd/m2 to be an ideal average for peak output, we calibrate all of our test monitors to that value. In a room with some ambient light (like an office), this brightness level provides a sharp, punchy image with maximum detail and minimum eye fatigue. It's also the sweet spot for gamma and grayscale tracking, which we'll look at on the next page.
We start with the calibrated black level. This can sometimes rise a bit from the monitor’s default state. We consider the tradeoff in contrast well worth the gain in color accuracy.
The EA294WMi runs with some good company. All of our best screens measure below .2 cd/m2 for calibrated black level. The NEC is in fourth place today, and seventh overall for the year.
Of course, NEC’s calibrated contrast ratio is quite good.
The EA294WMi finishes fourth in today's range of contenders and seventh overall in this metric as well. Any screen with a calibrated contrast ratio above 1000 to 1 is running in the top tier of performance. LG continues to improve the contrast of its AH-IPS panels. We saw even better numbers from AOC's Q2963PM, which uses the same glass as this NEC.
ANSI Contrast Ratio
Another important measure of contrast is ANSI. To perform this test, a checkerboard pattern of sixteen zero and 100 percent squares is measured. Our benchmark is somewhat more real-world than on/off measurements because it tests a display’s ability to simultaneously maintain both low black and full white levels, and factors in screen uniformity. The average of the eight full-white measurements is divided by the average of the eight full-black measurements to arrive at the ANSI result.
The EA294WMi stumbles a bit, and it’s not the fault of the grid polarizer. As you’ll see later, there are some screen uniformity issues that pull this number down, especially in the black areas of the checkerboard pattern. Because uniformity varies from sample to sample, another EA294WMi might very well measure better.
