Results: Viewing Angle And Uniformity
For off-axis viewing, there’s no better tech right now than IPS. You can sit as much as 45 degrees from center and still see a decent image. The light falloff is minimal and the color shift associated with TN monitors is virtually non-existent. In addition, with a monitor as bright as this, the effect can be further minimized at high output settings.
The HP looks like every other 27-inch IPS monitor we’ve tested: excellent. You can still see all the detail in the highest and lowest portions of the ramp pattern and there is no color shift as you move up to 45 degrees from the center axis position in any direction. If the monitor you’re reading this on is set correctly, you will see 11 bars in all five viewing angle photos.
To measure screen uniformity, zero percent and 100 percent full-field patterns are used, and nine points are sampled. In a change from previous reviews, we’re now comparing the results to other monitors we’ve measured. First, we establish a baseline measurement at the center of each screen. Then the surrounding eight points are measured and their values expressed as a percentage of the baseline, either above or below. This number gets averaged. It is important to remember that we test a single sample only, and that other samples of the same monitor can measure differently in this metric.
First up is black field uniformity:
Since the HP’s black level is so low, we had to take many readings to get usable numbers. For each point on the screen, we took 10 measurements and averaged the result. Yes, that’s 90 measurements! With a low 4.83 percent average deviation, you won’t see any dark or light areas in a black field. This is excellent performance.
Here’s the white field measurement:
The white field value of 7.5 percent isn’t quite as good as the black field number, but it’s still practically imperceptible. If you stare at the screen long enough, you’ll see a little light falloff in the upper-right portion of the panel. You won't see it in any normal image content, though. Again, this is excellent performance. While IPS is generally the best choice for good uniformity, all types of LCD technology have made huge improvements in this area.
Screen Uniformity: Color
Starting with our last monitor review, AOC’s Q2963PM, we’re adding a new uniformity test to our benchmark suite: color. The above measurements only address luminance. Now we’re measuring the white balance variation in an 80-percent white field pattern. The results are expressed as a variation in Delta E (in other words, the difference between the highest and lowest value).
Unfortunately, we only have these two monitors in the database at present. The E271i is especially good, with only a .34 variation in Delta E. Meanwhile, the AOC ranges from a high of 2.6 to a low of .48, which you still wouldn't pick up with a casual glance. Only our i1Pro knows the truth.