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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.
Uncalibrated – Maximum Backlight Level
27" QHD gaming monitors usually mean premium pricing even for TN models. IPS commands the top of the price spectrum here, and three of our group, including the AG271QG, employs that technology. The other three are Asus’ PG279Q and MG279Q, plus Dell’s SE2717H which is the lone FHD panel. The two TN screens, which adorn the AOC AG271GX and Asus MG278Q, use FreeSync adaptive refresh.
With ULMB in the feature list, the AG271QG needs all the output it can muster. It rises to this requirement with a bright 369.4317cd/m2 maximum white level. That’s right up at the top with its FreeSync-enabled companion display and the premium Asus PG279Q. With a .3187cd/m2 black level, sequential contrast measures an impressive 1159.2:1; better than most TN and IPS panels we’ve seen. Of course, we don’t use ULMB in our gameplay and we suspect most others don’t either. It’s not usually worth giving up G-Sync for. We’ll show you its effect on this display in the calibrated luminance results.
Uncalibrated – Minimum Backlight Level
Running the brightness slider down to the bottom yields 39.6246cd/m2 which is a little on the dim side for gaming in a dark environment. Click the control up to 7 for a more comfortable 50cd/m2. The black level remains solid at .0349cd/m2 which means contrast remains at a consistent level throughout the AG271QG’s output range. Things are looking good so far for image depth and quality.
After Calibration to 200cd/m2
We measured output after calibration in both G-Sync and ULMB mode. As you can see, the backlight strobe takes a huge bite out of the white level; 66% in fact. And that’s at the pulse-width control’s maximum setting. Turning it down has a positive effect on motion blur but makes the picture too dim for practical use. Contrast is also affected but to a lesser extent.
You’ll also notice that in G-Sync mode, contrast has dropped by almost 30% from the default number. This is due to fixes we made to gamma and to our grayscale adjustments. It was done to improve color saturation accuracy and detail rendering at the brighter end of the scale.
ANSI Contrast Ratio
The ANSI contrast result is down a bit from the sequential thanks to slight hotspots in the upper-right and lower-left corners of the screen. It appeared in our uniformity tests as well, though it doesn’t quite qualify as IPS glow. Still, we’d like to see a little more overall dynamic range here. Other AG271QG samples may measure better than ours. The rest of the screen looks pretty good when showing test patterns and our gaming tests did not reveal anything to be concerned about.
