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 are covered on page two.
Uncalibrated – Maximum Backlight Level
The XG2530 is the fifth 25” 240Hz monitor we’ve tested so far. The previous four are Asus’ PG258Q, Acer’s XB252Q, Alienware’s AW2518H, and AOC’s AG251FZ. The first three are G-Sync screens while the fourth is FreeSync. To round out the group, we’ve included a 27” IPS display, ViewSonic’s XG2703-GS with G-Sync and a 165Hz refresh rate.
ViewSonic claims 400cd/m2 for the XG2530 but we only measured 356.0925cd/m2. This isn’t a big deal, because there is no backlight strobe to compensate for. G-Sync monitors always include ULMB which can reduce output by 60% or more. FreeSync screens don’t have this limitation. There’s more than enough light for any indoor environment.
Of the TN panels, the XG2530 offers the best black level, mainly due to its slightly dimmer backlight. You can see when contrast ratios are calculated that ViewSonic takes the top spot with its 27” IPS screen and runs mid-pack with its TN offering. It should be noted that the differences shown here are barely visible, and with a little room light they will be impossible to spot. Only a significant rise in contrast will make an appreciable change to image depth. With more VA panels and zone-dimming HDR screens just around the corner, that wish will soon become reality.
Uncalibrated – Minimum Backlight Level
The XG2530 can only go down to 78nits or so, which is a tad brighter than we’d prefer in a totally dark room. Once calibrated, minimum output drops to 58nits which is less fatiguing during those all-night gaming sessions. Contrast remains very consistent at 964.3:1. Don’t be tempted by the DCR option in the OSD—it will only clip detail and make dark areas of the image more difficult to see.
After Calibration to 200cd/m2
During our calibration, we worked with the Black Stabilization control to optimize shadow detail and firm up low-end gamma. It worked well but cost us a little contrast, which is now down to 714.5:1. This is the weakest area of the XG2530’s image and something we can just forgive thanks to its excellent color accuracy and screen uniformity. We know this panel is capable of more given the numbers posted by the other 25” displays. And IPS remains the image depth winner with an excellent 1039.4:1 result. Remember that this monitor is designed for ultimate gaming performance, not perfect image fidelity.
ANSI Contrast Ratio
ANSI contrast comes down a little from the sequential number due to a couple of tiny hotspots in our checkerboard pattern. Overall uniformity is quite good but again. TN is not the technology to deliver impressive contrast numbers. IPS makes a good showing here, but what we really need is 240Hz and adaptive refresh behind a VA panel.
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