Big, Bright, and Not All Business:
Using A Commercial Projector in Your Family Room-Part 2
Editor's Note: In Part 1 of this article , contributing editor M. David Stone explained how high-brightness business projectors differ 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 these projectors measured for brightness and fared in the key areas of color, contrast, and black level, and describes how an ambient-light-rejecting screen affects image quality in different lighting conditions.—Rob Sabin
Color Performance for Film and Video
Our first goal was to see how easy these projectors were to optimize and how well they performed after optimization. Here's a snapshot look at the performance for each of our three sample business 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).
BenQ LH770 Performance
Video Optimized Modes. The LH770 lets you save changes to each color mode. Optimize each one, and you can use whichever mode delivers the best balance of brightness and image quality for the current level of ambient light as it changes through the day as a consequence of changes in sunlight coming in or turning lights on or off.
The LH770 delivers acceptably realistic looking color despite some minor compromises. Adjusting color so blue skies don't occasionally turn green in sRGB mode, for example, yielded a slightly bluish black in a dark room. However, it was not noticeable with ambient light. Also, after adjusting brightness and contrast using display setup test patterns, Bright mode looked a little washed out. After optimization, the three most useful color modes were Bright for highest brightness; Vivid, which was almost as bright, but delivered better color accuracy and contrast; and sRGB for the best color accuracy and contrast.
Color Preset Performance. Note that we tested an early production unit of the LH770 with firmware version 1.00 that suffered obvious color inaccuracies in all of its color preset modes, notably reds with a blue shift in some modes, and blues shifted toward red or green in others. After color adjustments, however, most colors in most scenes were well within a realistic range.
BenQ says the color was tuned this way initially for some specific commercial applications, but firmware version 1.02, available on newly shipped units and to existing owners via a firmware update, provides a more color-accurate preset for film and video. According to BenQ, selecting the sRGB mode and turning off the DLP Brilliant Color feature delivers a color profile similar to BenQ's typical Cinema preset for those who wish to do less tuning out of the box. Users who need to perform the update should contact BenQ customer support for instructions.
Brightness. In its brightest mode, before adjusting brightness, contrast, or color, the LH770 ANSI lumen measurement was roughly 80% of its rated 5,000 lumens, which BenQ says is a little lower than expected, and may also be due to its being an early production unit. The measurements for each color mode in Normal and Eco power modes (HDMI input, lens in its widest angle position) are as follows for the brightest mode with default settings and for each mode with optimized settings in that mode:
BenQ LH770 ANSI Lumens
Low Brightness Mode. Eco mode lowers light output by roughly 21%, delivering 2,474 lumens for the brightest mode with optimized settings.
Zoom Lens Effect on Brightness. The 1.5x zoom lens curtails light by roughly 23% at the full telephoto end of the range, giving a measured 3053 lumens in Bright mode with default settings.
Brightness Uniformity. At 73% brightness uniformity with the lens at the wide angle end of its range and 76% at the telephoto end, the LH770 does better for uniformity than most inexpensive home theater projectors. A solid white image showed a touch higher brightness at the bottom middle and left, slowly dropping going up and to the right, but the difference is too little to see with movies or video.
Epson Pro G7905U Performance
Video Optimized Modes. In addition to its predefined color modes, the G7905U can store 10 customized settings, which lets you calibrate, store, and retrieve optimized settings for multiple lighting conditions, from nighttime with lights turned off to bright daylight streaming through windows. It can also store 10 sets of combined settings for its powered zoom, focus, and lens shift, so you can easily switch between, say, 16:9 and Cinemascope 2.41 aspect ratios if you want a constant image height setup. It can even store three sets of geometric correction settings.
After optimization, the G7905U delivers a close color match to a reference projector along with suitable contrast and black level for video and film in Dynamic, Presentation, and Cinema modes. Even Cinema, with the lowest brightness of the three, delivers a whopping 5,115 lumens at 16:9 aspect ratio, making it bright enough to light up a 180" 1.0 gain screen in moderate ambient light.
Color Preset Performance. The G7905U offers highly watchable video with default settings in all modes except Dicom Sim, which is meant for x-rays and the like. Cinema delivered the best contrast and most accurate, neutral color. It also did the best job holding subtle gradations in midtones. Dynamic and Presentation modes came in just a bit lower on all three scores. Multi-Projection and sRGB modes are best described as usable, but lacking saturation. They also delivered lower contrast and sense of depth than the other modes. Brightness. With default settings, the G7905U test unit essentially matched its 7,000-lumen rating, measuring 7,049 ANSI lumens. That's a touch brighter than the G7905U we looked at for a Road Test back in 2016, but within the expected variation from one unit to another.
As mentioned earlier, the more relevant brightness for this discussion is for the non-native 16:9 aspect ratio, where the G7905U uses only 90% of its 16:10 imaging area. For each color mode in both Normal and Eco power modes, the ANSI lumen measurements for a 16:9 image in the brightest mode with default settings and in each optimized color mode are as follows (HDMI input, lens in its widest angle position):
Epson Pro G7905U ANSI Lumens
|With Optimized Settings||Normal||Eco|
Low Brightness Mode. Eco mode reduces brightness by 22%, leaving the optimized version of the brightest mode at a solid 4,858 ANSI lumens.
Zoom Lens Effect on Brightness. The standard 1.6x zoom lens for the G7905U curtails light by only 16% at the telephoto end of the range, a lower than typical drop in brightness compared with the wide angle end for this level of zoom. For Bright mode with default settings, Normal power, and 16:9 aspect ratio, it translates to 5,265 ANSI lumens.
Brightness uniformity. The measured 80% uniformity for the G7905U is lower than the 89% we saw with the earlier test unit, but high enough that few, if any, will consider it a problem. A solid white test image shows the bottom left corner as the brightest area, with brightness dimming slightly going up and to the right. With video and film, the difference was impossible to see.
Optoma ZH500T Performance
Video Optimized Modes. The ZH500T can save modifications to only one color preset mode. Make any change to any preset, and the changed version immediately becomes the new, and only, User mode. Rather than adjusting color and other settings every time you change the color mode, it makes more sense to pick one to modify and save, and use the default settings for other color modes you may switch to occasionally when you need a different brightness.
We suspect most people will chose Bright mode as the preset to start with for video optimized settings for the same reasons we did. In addition to it being the brightest mode, we were able to adjust the color to fall within a realistic looking range in the vast majority of clips we looked at without changing the measured brightness significantly.
With its default settings, Bright mode has a slight green bias that shows primarily in skin tones. However, it can be adjusted to a nearly neutral color. And at 4,195 ANSI lumens, it is bright enough to fill a 180-inch diagonal 1.2-gain screen in moderate ambient light.
Color Preset Performance. Straight out of the box, Movie mode has a slight green bias, but less so than Bright with default settings, while Blending mode has the most obvious green shift. Presentation mode offers more accurate color by default, but loses subtle gradations in midtones, which makes rounded objects like close-ups of faces look flat instead of three dimensional. Dicom Sim is designed for medical images like x-rays. For the most accurate color out of the box, but lowest brightness, sRGB delivers 1,350 ANSI lumens—enough to light up a 100" 1.2-gain screen in moderate ambient light.
Brightness. The ANSI lumen measurements for each color mode in Normal and Eco power modes (HDMI input, lens in its widest angle position) are as follows:
Optoma ZH500T ANSI Lumens
|Bright (after adjustment)||4190||2856|
Low Brightness Mode. We measured Eco mode at 32% lower brightness than Normal mode, or roughly 2,860 lumens for the video optimized setting.
Zoom Lens Effect on Brightness. The 1.6x zoom lens curtails light by roughly 32% at the full telephoto end of the range, for a measured brightness of 2,860 ANSI lumens in Bright mode with default settings.
Brightness Uniformity. The ZH500T's brightness uniformity came in at a solid 85% with the lens at its full wide angle setting and 74% at the full telephoto end of its range. With a solid white image, the bottom center is the brightest area, with the brightness dimming slightly going up and to each side. Even at the full telephoto setting, the uniformity is better than most inexpensive home theater projectors offer, and too little to see with photorealistic images.
|Review Contents:||Color Performance||Contrast and Black Level||Conclusion|