Test Bench

FULL- ON/FULL- OFF CONTRAST RATIO: 1066:1 (SDR); 1,725:1 (HDR)

Pre-calibration measurements were made with the Viewsonic PX747-4K’S Movie picture preset active. Postcalibration measurements were made in the same mode. All measurements were made using a Stewart Filmscreen Cima 1.1 gain projection screen.

The projector’s highest SDR contrast ratio was achieved with the Movie picture preset's default settings and Dynamic lamp mode active. With this combination, black measured 0.057 ft-l and peak white 60.8 ft-l for a contrast ratio of 1,066:1, a weaker showing than other 4K projectors we’ve recently tested. Contrast ratio in the same preset with Normal lamp mode active was 479:1. In HDR display mode, the Viewsonic’s measured contrast ratio was 1,725:1. Maximum light output was 106.6 ft-l with contrast set to maximum in Bright mode with the Eco mode switched off.

Before calibration, the Viewsonic’s default Normal color temperature preset in Movie mode displayed below-average grayscale tracking, with the Delta E averaging out to 9.8. After calibration, that average improved substantially to 0.8, with a high of 1.6 at 100 percent brightness. (Delta E is a figure of merit indicating how close the color comes to the standards, either D65 for the white point or the color coordinates for each of the primary and secondary colors that define the color gamut under test. Values below 3 are generally unnoticeable.)

With the default settings active in Movie mode, the PX747-4K’S color points measured far off the mark, with the Delta E averaging out to 10.6. While the projector does provide color management system controls, these proved only moderately effective in improving color point accuracy, with the post-calibration Delta E averaging 5.4.

Gamma closely tracked a 2.2 target for most of the range when the 2.2 Gamma preset was selected. In HDR mode, the PX747-4K’S light output on 2, 5, 10, 25 and 100 percent white patterns ranged from 230 to 238 nits. The ViewSonic’s coverage of the P3 color gamut was 57%, which is well below other 4K/ Hdr-capable projectors I’ve tested.

Picture uniformity was good: white full-field test patterns showed minimal brightness drops between the center and edges of the screen, and no color shifts. Our suite of video processing tests revealed uneven performance, with the Viewsonic showing substantial green clipping and failing both 2:2 and several 2:3 pulldown tests.

Input lag with a 1080p source measured 42.3 ms, making the VL7860 a decent option for high-def gaming.