11th July, 2008
Is There Something Better Than A 2.35:1 Screen?
Brent Butterworth
Most integrators consider constant-height 2.35:1 projection systems the ultimate in video, but after a chat with the folks at Performance Media Industries, Ltd. (PMI), we’re not so sure. From our conversations with PMI, a well-known home theater design firm, we can’t tell if the company’s recent efforts will result in the greatest video experience ever, or if they’re an exercise in video geekery that only an Imaging Science Foundation course instructor could appreciate. But the subject is definitely interesting enough to warrant a full explanation.
First, let’s recap the constant-height concept that has already swept the custom home theater industry. Constant-height combines a superwide 2.35:1 (or CinemaScope) screen, an anamorphic lens that stretches a projector’s image to fill the screen, and a processor that corrects the picture geometry so everything looks right. As the name implies, the height of the image is always the same. Motorized black masking fills the sides when you’re watching narrower material, like 1.78:1 (or 16:9) HDTV or old-school 1.33:1 (or 4:3) video.
These superwide screens are popular because they produce a cinematic effect, and because they deliver big pictures in rooms with 8-foot ceilings. But constant-height technology has drawbacks. In a room with a 10- or 12-foot ceiling, your 1.78:1 HDTV picture probably isn’t going to be as big with a 2.35:1 screen as it would be with a 1.78:1 screen. Constant-height systems also put video images through a lot of extra electronic and optical manipulation.
What’s The Big Idea?
PMI says it has a better solution. It’s called (with no small amount of self-promotional flourish) PMI 2.0. We at The Integrator have been such enthusiastic proponents of constant-height that we had to find out what PMI is up to.
“The question we’ve always run into is, ‘How do you create a screen that will take you into the future?’” said Terry Hill, PMI’s general manager. He went on to explain that PMI 2.0 involves not a new and improved version of his company, but a screen with an aspect ratio of 2.0:1. “It’s a canvas that provides the best starting point for both 1.78:1 and 2.35:1,” he explained. “It means that you don’t have to compromise sports in 16:9 high-def for movies in 2.35:1, or vice versa.”
The most profound advantage PMI claims is that its new scheme delivers a better picture because it requires no additional video processing and no anamorphic lens. The purer signal path eliminates the potential for artifacts that extra video processing introduces, and also eliminates the distortion, chromatic aberration, and loss of detail that an additional lens might cause.
Constant-height systems have the advantage of using the entire surface of the DLP chip in the projector no matter what widescreen aspect ratio is shown; using the entire chip can deliver extra brightness and can make individual pixels less visible on-screen. In comparison, PMI 2.0 uses the full DLP chip only at the chip’s native 1.78:1 aspect ratio. Hill said he feels that PMI 2.0’s benefits outweigh this disadvantage.
The PMI 2.0 spec calls for a screen that’s larger than what we usually see now. The first PMI 2.0 theater will have a maximum screen size of 150 by 75 inches—this in a room with the not-humongous interior dimensions of 20 by 26.5 feet. “With 4K projectors already out, and even higher resolutions having been demonstrated, soon we’ll be at the point where no matter what screen size you have you won’t be able to see pixels from anywhere in the room. We’ll be able to go beyond where we are now with viewing angles,” Hill elaborated.
Hill said that for now, PMI won’t be using the full area of the screen. Eventually, when the client moves to a higher-resolution projector, more of the screen could be used.
“Once the resolution is high enough that you can’t see the pixels, the discussion then moves to things like presence and what field of vision you want the screen to take up,” he continued. “There are limits to the field of vision you can take in. If you make the screen too large it tends to make you sick to your stomach from all the motion.”
What’s the Future?
PMI 2.0 requires nothing new in terms of screen technology, but it does demand a projector with a motorized zoom lens and a servo that can return dependably to a particular zoom setting. “There are already about 20 different projector models that will do this,” Hill reported, “and we’re working with vendors now to create something that meets our specific needs.”
For the near future, PMI 2.0 will be an option only for the world’s elite theaters. According to Hill, it demands a ceiling height of at least 12 feet; a projector that currently costs about $200,000; and a screen that costs $30,000 and up. He predicts the projector cost will come down substantially, but the screen cost won’t.
So will PMI 2.0 sweep the custom home theater industry? That’s impossible to say at present, and not just because the first PMI 2.0 theater won’t be completed for a few more weeks. PMI 2.0 sounds fascinating to the tech-obsessed staff of The Integrator, but its ultimate success will depend on whether the company can develop a concise sales pitch and a compelling demo—and whether other design firms will embrace something invented by a competitor.
Posted at 8:36 am |
On August 18, 2008 at 2:09 am Alex said:
August 18, 2008 at 2:09 am
Your blog is interesting!
Keep up the good work!