Runco LS-10i 3-Chip DLP Projector Page 2


I’m frustrated that I used up all my clever extreme-brightness superlatives on the single-chip Sharp XV-Z17000 last issue, as it pales in comparison to the three-chip LS-10i. Peak light output was an unbelievable 42 footlamberts (ftL) on my 102-inch, 1.0-gain screen. By far the brightest projector I can remember measuring, it’s brighter than many plasmas when showing a full 100-IRE white image. I took a moment to ponder what fi repower of that magnitude can really do. Startle deer. Signal the ISS. Etch circuit boards. Fuse hydrogen. Project a roughly 19-ftL image on a 152-inch diagonal screen. (That’s about what I measured with JVC’s excellent DLA-X7 on my 102.) Yeah, you can get a big, big image with this thing.

But in this case, getting that much brightness can come at the cost of good black levels. Two LS-10i features work to enhance contrast and black level: ConstantContrast and AdaptiveContrast. With these disabled, the contrast ratio is a rather normal 2,799:1.

Runco describes ConstantContrast as “frame-byframe contrast correction.” It’s effectively an auto-iris, monitoring the video signal and opening or closing an aperture to dim dark scenes and keep bright ones bright. On paper, it works great. While enabled, the contrast ratio rose from 2,800:1 to more than 12,000:1. But I chose to turn it off. The problem was that I could see it working: Brightness changes in the image lagged behind changes in the video signal. This pulsing is common with auto-iris systems, though ConstantContrast also had a subtle color shift associated with it. Other DLP projectors have a similar circuit, and I’ve turned it off on those for the same reason.

AdaptiveContrast is a real-time gamma adjustment, making brighter parts of the image seem brighter and darker parts darker. It’s not actually improving the contrast, just one’s perception of it — sort of like tuning the brightness and contrast controls past their nominal setting. With AC off, the image didn’t appear quite as punchy, but it was a lot smoother and more natural looking.

Even when I used the LS-10i in its lowest (on paper) contrast setting, the excellent light output did a decent job covering for the merely average blacks. A better LCoS projector like the JVC does have more visible depth, but I didn’t fi nd the LS-10i’s image to be washed out or otherwise lacking. That said, 102 inches is about as small a screen as you’d want for this projector, unless you go with a negative-gain model. Though that seems kind of a waste here: Even when the Economy lamp setting is activated, there’s so much light output potential that you’re better off getting a larger screen than one with negative gain.