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
The largest displays we normally review are 32” diagonal, but one other 40” panel has passed through our labs: the Philips BDM4065UC. We’ve also included the BDM3270. Both are VA-based monitors. Remaining displays include Acer’s XB321HK, and BenQ’s PV3200PT and PD3200U.
AOC claims 300cd/m2 for the C4008VU8, but our sample could only manage 266.3735. For most applications, it isn’t a big deal, but it does mean there’s less headroom for the uniformity compensation feature. You’ll see in the calibrated test below how that affects brightness and contrast. It should be noted that a panel this large will likely be run at a lower output level anyway. We found 200nits to be painfully bright in actual use.
As always, VA rules the black level test with numbers far below what’s possible from IPS technology. This results in fantastic contrast, 4788.4:1 in AOC’s case. It’s a third-place finish but almost five times greater than the next-best PV3200PT.
Uncalibrated – Minimum Backlight Level
We’d like to see a lower minimum backlight level than 74.8738cd/m2, but at least that means precise brightness control. Each click is less than 2cd/m2, making it easy to precisely tailor light output. The black level remains in third place, but contrast jumps up to second and remains consistent at 4702.6:1.
After Calibration to 200cd/m2
After calibration, we measured luminance with and without uniformity compensation. Our adjustments cost almost nothing in contrast, but uni-comp will reduce the white level almost 50%. Since there is little change in black level, sequential contrast drops by roughly the same amount. If the C4008VU8 had serious uniformity issues we might use it, but our sample posted top marks in our tests, which you’ll see on page five.
ANSI Contrast Ratio
ANSI contrast is a bit below the sequential value but not enough to be noticeable. Uni-comp reduces the number further, but the AOC is still well above the IPS panels here. The panel part used is of high quality with no bleed or glow issues that we could see or measure. This level of contrast is well beyond the norm and significantly elevates image quality. We only wish the C4008VU8 had HDR support. Perhaps AOC will add it in a firmware update.
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