4K TV Reviews

Full-On/Full-Off Contrast Ratio: Unmeasurable

The measurements here were made using CalMAN measurement software from SpectraCal, together with a Konica Minolta CS-2000 and Klein K-10A color meters, and the Murideo Fresco Six-G 4K pattern generator. The peak white levels given below were rounded here to the nearest foot-lambert/nit.

At a peak white output (SDR Rec. 709 mode, post calibration) of 44 ft-L (measured in ISF Expert Dark Room Picture Mode, with the OLED Light at 43, Contrast at 79, Brightness at 52), the set’s black level could not be measured (in effect, it was totally black).

In SDR and the ISF Expert (Dark Room) Picture Mode, the pre-calibration grayscale Delta E values, at a peak unclipped white level of 60 ft-L (204 nits), ranged from a low of 0.74 at 10% brightness to a high of 1.55 at 100%. These levels were so low that we left all of the White Balance controls in their default setting (all zero). But we did reduce the OLED Light setting to drop the peak white level to a more comfortable dark room level of 44 ft-L (150 nits). This changed the Delta Es slightly, but they remained at or below 2.16 (at 30%).

The pre-calibration SDR color Delta Es ranged from 1.35 in yellow to 2.49 in red. After calibration (with the only control change, as above, a reduction in the peak white level using the OLED Light control), the minimum was 1.28 in magenta and the maximum 2.39 in red. The average gamma, with the set’s Gamma control on 2.4, was 2.43.

(Delta E is a figure of merit that indicates how closely a display adheres to the color standard. Experts generally agree that at levels below 3 to 4, the result is visibly indistinguishable from perfect color tracking. Delta E may be used to characterize either white balance [grayscale] or color.) We also calibrated the LG’s grayscale for HDR10 in the HDR Cinema Picture Mode. In the default positions for the OLED Light control (100) and Contrast (100), and with Brightness on 50, the pre-calibration grayscale Delta Es ranged from a minimum of 0.064 at 10% brightness to 3.5 at 65%. Post-calibration, the lowest was 0.064 at 10% and the maximum 2.29 at 30%.

The post-calibration HDR10 gamma (not adjustable here, and now more correctly called EOTF, for Electro-Optical Transfer Function) followed the specified curve for HDR (PQ for Perceptual Quantization) very closely, apart from a slight reduction in brightness between 15% and 40%. The brightness at 50% measured 102 nits (29.8 ft-L), and the peak white at 100% measured 668 nits (195 ft-L).—TJN