To learn about our HDR testing, see our breakdown of how we test PC monitors.
To switch the CM3271K into HDR mode, we applied an appropriate signal and toggled the manual control in the OSD. It won’t change over automatically despite an HDR option labeled “Auto”. Once Auto is engaged, all image controls are locked out.
HDR Brightness and Contrast
The CM3271K has plenty of brightness available for HDR content with a peak of over 464 nits. There is no dynamic contrast in play here, so the black level is about the same as it is for SDR. Contrast is therefore just 1,009.4:1 in HDR mode. Though the EOTF luminance curve is accurately rendered, this monitor doesn’t provide any more impact with HDR content. It’s displayed correctly, but there is no visual benefit to running HDR mode.
Grayscale, EOTF & Color
Despite the lack of extra contrast in HDR mode, the CM3271K does display HDR content accurately. Grayscale errors are minor with a slight purple tint visible from 40% and higher. The luminance curve is close to spec with a soft transition to tone-mapping at 65%.
There is plenty of color available for the CM3271K to cover both DCI-P3 and a large portion of Rec.2020. When measured against the DCI standard, only red and green come up slightly short. Inner targets are a bit over-saturated which is fine since it makes the image look more vivid. Rec.2020 is the same story with inner targets nearly spot-on and only a little less saturation at the triangle’s perimeter. This is some of the best HDR color performance we’ve seen to date.
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