Sound & Vision - - CONTENTS - By Al Grif­fin

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.


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.


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.


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.

The PX747-4K sports a pair of HDMI in­puts, one of which sup­ports 4K/60HZ sig­nals with HDR.

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