Editor's Note: In this two-part report, we examine the suitability of commercial business projectors for use with video and movies in high-ambient-light home theater environments. For this first section, contributing editor M. David Stone covers how this class of product differs from traditional home theater projectors, how we went about our testing of three commercial projectors, and some basic performance characteristics of our samples. In Part 2, he discusses how they fared in the key areas of color, contrast, and black level, and how the use of an ambient-light-rejecting screen can affect image quality with these high-brightness projectors.—Rob Sabin
If you follow the projector business the way we do here at ProjectorCentral, you may know that there is a growing class of 5,000 to 7,000-lumen projectors, both lamp-based and laser models, that are marketed for business but rarely for home theater use. There may be some sound logic behind this, in that there is often a trade-off between higher brightness and the deeper black levels and better contrast persued by home theater enthusiasts—it's difficult, and usually costly, to have it all. But with more and more consumers opting for high-ambient-light home theaters as a big-screen alternative to expensive, giant flatscreen TVs, we decided it was time to take a closer look at this projector category and see just how well these models perform in that role.
To do so, we gathered three projectors, the BenQ LH770 (5,000 lumens, $5,000), Optoma ZH500T (5,000 lumens, $2,999), and Epson Pro G7905U (7,000 lumens, $4,387). The key appeal of these is simple: They all deliver plenty of lumens at much lower cost than home theater projectors with the same brightness. At this writing, 1080p or 4K home theater projectors with 5,000 lumen or higher ratings start at $15,000—five times more than the Optoma ZH500T. The open question is whether less expensive models like these can deliver good enough image quality—including the aforementioned contrast and black level, as well as color accuracy—to make them a good fit for watching film and video in a home environment.
Among our three samples, the Optoma ZH500T and BenQ LH770 are laser-based, 1080p DLP models. The G7905U is a lamp-based, 3LCD projector with 1920x1200 (WUXGA) native resolution and pixel-shifting 4K enhancement. And if you're looking for true 4K, note that there are models in this brightness and price class becoming available now as well. Most notably, the $5,199 BenQ LK952 and $4,999 Optoma 4K550 both offer 5,000-lumen ratings. We anticipate reviewing both.
We focused primarily on home use in our tests, but the results apply to sports bars and similar venues faced with some degree of ambient light. Before we discuss what we found, however, it is important to understand that this story isn't meant as a formal review or face-off of these projectors. Of course, we had to look at individual projectors to test the concept, and we'll discuss what we found with each one. But the real subject we wanted to explore was how well high brightness business projectors can handle video and film in rooms with ambient light, and whether pairing them with an ambient light rejecting (ALR) screen was a useful, absolutely necessary, or unimportant part of the equation. To that last end, we acquired through the assistance of Screen Innovations a screen sample with their popular Slate 1.2 ambient-light-rejecting material. More about that in Part 2 of this article.
How Do Business Projectors Differ From Home Theater Projectors?
There are some general issues to keep in mind when looking at projectors in this 5,000 to 7,000-lumen class.
Brightness. Brightness ratings and the measurements in most projector reviews are based on using the entire imaging chip. But for film and video, they're meaningful only for projectors with a native 16:9 aspect ratio, like the BenQ LH770 or Optoma ZH500T. For the native WUXGA 16:10 aspect ratio used in some business models, like the Epson Pro G7905U, the brightness for 16:9 images is about 10% lower, because the projector uses only 90% of the imaging chip area that it uses for 16:10 images. In this report we'll adjust for that when discussing the G7905U. Usually, however, you'll have to make the adjustment yourself.
Also keep in mind that most DLP projectors designed for business—including the BenQ LH770 and Optoma ZH500T—have a substantially higher white brightness than color brightness, while 3LCD projectors like the Epson Pro G7905U have matching white and color brightness. The high white brightness for DLP models makes presentations and documents with white backgrounds brighter. But color images, like most film and video, may not be as bright as you would expect from a 3LCD projector that the DLP model matches for white brightness. BenQ says that for any given measured difference between white and color brightness, the perceived loss of brightness for color images is far less extreme with its laser technology than with lamps, but we have not yet tested that claim.
Setup. Projectors in this class tend to be big and heavy, which can make setup a little harder. The three we're including in this discussion range from 23.3 pounds for the Optoma ZH500T to 30.4 pounds for the BenQ LH770. The Epson G7905U falls in the middle, at 28.4 pounds.
Also, because these projectors are intended for business use, many of them—including both the ZH500T and LH770—have lens offsets meant for a ceiling mount or a low table. The G7905U is an exception, with a large enough vertical lens shift to project easily from a ceiling mount, a low table, or the equivalent of a high bookshelf behind and above the viewing area, all without needing to tilt the projector and then square off the image with keystone correction.
Although the G7905U is the only one we looked at that offers such substantial horizontal and vertical lens shift range, and the only one with powered lens shift, most projectors in this class have at least some flexibility for positioning. The LH770 and ZH500T both offer smaller manual vertical and horizontal lens shifts, for example, and all three models provide a 1.5x or 1.6x zoom as tested. The G7905U also offers a choice of 10 other lenses, ranging from an ultra short throw fixed lens to a long throw zoom.
Maintenance. Part of the appeal for many projectors in this class, including the LH770 and ZH500T, is that they're built around laser-phosphor light sources and require little to no maintenance—a particularly welcome touch for applications like sports bars. Both models offer IP5X dustproof certification, with BenQ touting a guaranteed 20,000 hours of maintenance-free operation and Optoma claiming 20,000 hours "virtually maintenance free." The lamp-based G7905U offers only a 3,000-hour lamp life in Normal mode and 4,000 hours in Eco. It also requires occasional cleaning and replacement of the air filter.
Video Processing and Color Adjustments. Most projectors marketed for business have few or none of the video processing features that are common in home theater projectors. The G7905U offers frame interpolation (FI), but it is not available with a 4K connection to a video source. And when it is available, you can turn on either FI or 4K enhancement, but not both.
Some business models also skimp on controls for color calibration. However, all three of the models we looked at make color adjustment easy with CMS (color management system) controls for hue, saturation, and gain—or hue, saturation, and brightness for the G7905U—for each primary and secondary color (RGBCYM).
Contrast, black level, and shadow detail. None of the three models we looked at has the jaw dropping black level, contrast, or retention of shadow detail you would expect from a home theater projector at this price. And that's probably true of virtually all, if not all, projectors in this category.
That said, using a standard white screen in a dark room, the LH770, ZH500T, and G7905U are all in the same league on all three scores as many less expensive home theater projectors. And pairing them with the ALR screen we used for testing makes black level, contrast, and shadow detail still better, even in a dark room.
3D Performance. The high brightness for this class of projectors could make it feasible to watch 3D movies in ambient light, but you can't prove that from the three projectors we included here. The ZH500T's 3D mode is roughly as bright as its lowest brightness 2D mode, making it only about half as bright after taking the glasses into account. The LH770's 3D mode is noticeably dimmer than its lowest brightness 2D mode. On the plus side, we didn't see any crosstalk with either projector, and both showed only the typical minor 3D-related motion artifacts. Epson's 3D projectors typically deliver 3D at a higher percentage of their top 2D brightness, but the G7905U doesn't support 3D.
Input Lag. The fastest measured input lags for the three projectors we tested are 44 ms for the G7905U, 50 ms for the LH770, and 76 ms the ZH500T. Casual gamers may find this sufficient. Serious gamers should look for projectors in this class that are designed for applications like flight simulation that require short input lags.
Fan Noise. High brightness projectors typically have noticeable fan noise from anywhere in a quiet room, even in Eco mode. For applications like sports bars this won't be an issue even with full power. For home use, anyone who is particularly bothered by fan noise will likely want some form of acoustic isolation (again, even for Eco mode), and those who aren't usually bothered by fan noise may want to consider it if they require the use of Normal mode. Almost anyone will want to arrange for acoustic isolation if they need to use High Altitude mode—required at 2,500 feet for the ZH500T and at 4,921 feet for the LH770 and G7905U.
Rainbow Artifacts. As is typical for current generation DLP projectors, we didn't see many rainbow artifacts with either the LH770 or ZH500T. If you see them easily, however, and are bothered by them—or don't know if you are—our usual advice applies: You should buy from a dealer who allows easy returns, so you can judge them for yourself. As a 3LCD projector, the G7905U is guaranteed not to show rainbow artifacts.
Connections. Most projectors in this class have a wealth of connectors and most offer two HDMI ports. Some however, including the G7905U, have only one.