VIEWSONIC PX747-4K DLP PROJECTOR
SOUND&VISION has reviewed a number of DLP projectors over the past two years that display 4K-resolution images with the help of Texas Instruments’ XPR pixel-shifting technology. Two of those models, from Benq and Acer, are priced relatively high due to their use of laser light engines. The other model, Optoma’s UHD65, uses a regular UHP lamp to beam images and, at $2,500, represents a more affordable option. The latest 4K DLP to come our way is Viewsonic’s PX747-4K, which sells for around $1,260. Can its image quality compete with those other models at such a low price? Let’s investigate.
The PX747-4K is one of a pair of pixel-shifting 4K DLP projectors from Viewsonic, the other being the PX727-4K ($1,490). The key difference between the two is light output, with the PX747-4K spec’d to deliver 3,500 lumens versus 2,200 lumens for the the PX727-4K. To obtain such prodigious brightness, the PX727-4K uses an RGB color wheel with an additional white segment. DLP color wheels with a white segment are common in projectors used for business presentations, where maximum light output is a key concern due to the bright environments that the projector typically finds itself in.
For home theater use, however, there’s another important scenario where extra brightness can come in handy: displaying high dynamic range video.
The PX747-4K’S HDMI 2.0 input supports up to 4K/60HZ signals with HDR10 high dynamic range. (A second HDMI input on the projector’s back panel is HDMI 1.4.) Viewsonic’s specs additionally cite support for 10-bit color depth, though no information is provided for coverage of the P3 color gamut used for mastering 4K/HDR programs. The projector has a 1.2x optical zoom and a throw ratio of 1.47 – 1.76. Lamp life is 4,000 hours for normal use, and 15,000 hours in Dynamic Eco mode.
The compact PX747-4K has a white case with rounded edges and an array of control buttons on top. Lens zoom and focus controls are provided in a recessed area also located on the top surface. Along with its HDMI jacks, the projector’s other back-panel connections include a VGA input, a USB 2.0 port, an RS-232 control port, and a 12-volt trigger output.
Viewsonic’s remote control for the PX747-4K is on the mini side but features a notched back to allow for a better grip. The keypad is fully backlit—always a good thing for a projector—and provides a set of direct input buttons near the top along with controls to directly access picture modes and important settings like brightness, contrast, and HDR mode.
SETUP
I installed the PX747-4K on a low table with the lens positioned 10 feet away from a 92-inch diagonal, 1.1 gain Stewart Filmscreen Cima screen. Like most budget projectors, there are no vertical or horizontal lens shift controls, though two adjustable feet allow for minor image geometry adjustments, which can be carried out using a built-in test pattern. Once I had the picture locked in and focused, there was a small degree of visible light spray around the edges of the screen, though I didn’t find it particularly distracting.
With the projector’s Bright picture mode selected, I measured 107 footlamberts (ft-l) light output on a 100
IRE white pattern. Not bad for a compact, budget-priced projector! To optimize the Viewsonic’s picture for moviewatching, I selected the Movie picture mode, Normal color temperature preset, and 2.4 Gamma setting. From there I performed a grayscale calibration using the 2-point gain and offset adjustments. I also attempted to improve color point accuracy using the color management system controls in the projector’s 3D Color Management menu, though these only had a minimal effect.
Other settings I applied to tweak the PX747-4K included Dynamic lamp mode and the Color Enhancement slider in the Moviepro menu. With Dynamic mode selected, the Viewsonic managed a 1,066:1 contrast ratio with the Movie mode's default picture settings active. That’s hardly class-leading performance, though it was better than the 479:1 contrast I measured for the Normal lamp mode. (When measured in
HDR mode, contrast increased to 1,725:1.) Pushing the Color Enhancement slider to its midpoint or beyond helped a bit to increase color point accuracy. But the projector’s P3 color space coverage measured only 58%, a level well below that of other Hdr-capable projectors we’ve tested.
HD AND STANDARD DYNAMIC RANGE PERFORMANCE
The Viewsonic’s picture quality with regular Blu-rays was good overall, with skin tones and colors having a mostly natural look. Watching a scene from the Passengers Blu-ray where the space- and time-stranded couple get served at a bar by an android barkeep, their faces appeared neither overly flushed nor pale, while the brightly colored bottles of liquid in the background displayed the level of saturation that I typically see when watching this scene.
Watching the 2007 Blu-ray release of the film 2001: A Space Odyssey gave me a striking example of the projector’s black-level limitations, however. Letterbox bars at the top and bottom of the screen came across as a medium-gray instead of black. In a scene where proto-human apes huddle together for the night in a cave, the deep background shadows had a flat quality, and there wasn’t much detail to be seen in the creatures’ dark fur. Shots of a shuttle en route to a docking station also had a somewhat flat look, with not much contrast to be seen in the starfields pitched against the background of deep space.
Although the Viewsonic failed to impress me with its handling of blacks when watching Blu-ray discs, upconversion of 1080p images to 4K resolution was very good. Watching a scene from the “Noir” version of the Marvel character-based film Logan, the picture looked crisp and was free from noise. Fine gray tones in the black-and-white images were also accurately conveyed by the PX747-4K and I didn’t note any color tinting or other uniformity issues.
ULTRA HD AND HIGH DYNAMIC RANGE PERFORMANCE
Viewing the Ultrahd disc versions of Passengers and Logan gave me a good grasp of the projector’s handling of high dynamic range. Watching the same scene from Passengers
I had evaluated on Blu-ray, the highlights popped and the bar’s backlit surface glowed with greater intensity. The colored bottles lining the bar’s shelves didn’t look more detailed or saturated, however, which is an improvement I’ve noted when viewing this scene on other 4K/HDR TVS and projectors
that feature wide color gamut display capability.
Zipping ahead to a Passengers scene where the couple take a tethered float in space, I did note an increase in contrast and black detail over the
Blu-ray version of the same, but the highlights also seemed a bit blown out. I had the same impression when watching the Logan “Noir” version on Ultrahd: shadows were somewhat more detailed, but the beams of bright light poking through the holes in the abandoned plant where Logan tends to Charles Xavier had a searingly bright, burned-out quality.
The Viewsonic fared best when I watched the horror film Hereditary on Ultrahd Blu-ray. The opening scene features a slow zoom in on a miniature depicting the home where the family at the center of the story lives. The image looked impressively detailed and solid as the camera closed in on the domestic diorama. In a subsequent scene at a wake for the main character Annie’s mother, the play of light on her necklace really made it stand out. Seeing that detail during my second, Hdr-enhanced, viewing of the film gave me a different and more complete sense of what was going on in the narrative. It showed off HDR’S power to, for lack of a better term, “illuminate” fine visual details that add depth and complexity to the images flickering onscreen.