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Colorado got its first Dolby 3D theater in late May so I was finally able to A/B both RealD and Dobly3D over the past two days. My observations…
The film was Ice Age: Dawn of the Dinosaurs. Screen width was about 32’ in both theaters. I sat back about 1.5 screen heights in both auditoriums, perfectly centered. The Dolby3D theater was using a Barco. I watched the brightness level on the screen go down very slightly as the color wheel moved into position after the 2D previews. The spinning color wheel, per se, did not introduce any noticeable artifacts. The RealD theater was using a Christie. I don’t know the model number or lamp wattage of either but both seemed to be very bright for the 2D video, easily 14fl or above.
From my vantage point, the 3D was essentially perfect for both systems. No image ghosting and good depth although I thought the stereo image was slightly better with Dolby. It was also slightly sharper although I would attribute that to the Barco which seemed to have a slightly crisper image in 2D. As the end credits rolled, I walked up to the last row of each stadium theater. The credits appeared to be exactly on the screen but random artwork on each side of the letters appeared to be about 4’ in front of the screen in my normal seating position. At the back of the theater, they looked like they were much further in front of the screen with Dolby. In RealD nothing changed.
Then I walked down to about 1 screen height and to the edge of the screen. RealD had real ghosting issues. The first time I’d ever seen a double image in RealD. I’m sure it has to do with loss of polarization and the angle of light off of the silver screen. IMAX and others have produced charts of seating areas in their theaters that are not suitable for 3D viewing. Obviously, if you get too far off of center axis, the same holds true for RealD. Dolby had no ghosting problem at screen edge.
RealD also had more light loss than Dolby when the glasses were in place. Not a problem for most of the movie but in some cave scenes shadow detail, clearly visible without the glasses, disappeared with the glasses on. A brighter Christie might have fixed that.
Did Dolby3D have any issues? Absolutely. Since they fiddle with the color spectrum to achieve 3D, I was most interested to see if it changed the color of the movie in any manner. It certainly does. Ice Age is an ideal movie for an A/B because there is a lot of pure white in it; snow, ice, etc. Without glasses, snow-capped mountains look perfectly white. With RealD glasses they were still white although a bit subdued because of the gray filters. With Dolby glasses they took on a very slight hue of red/orange. If the viewer weren’t lifting their glass out of the way dozens of times a minute as I was the color shift probably wouldn’t be as apparent.
Most astonishing, though, was the green spectrum. There’s a point in the movie where everyone is surrounded by a dense green fog. In Dolby it looked like pea-green soup. In RealD it had more of the hue of a well maintained lawn of grass.
Supposedly, Dolby applies color correction in real time to the PJ video feed to compensate for the color shift introduced by the color wheel and the filtering on the lenses of the glasses. This is done with “look up” tables to ensure compliance with DCI color parameters. If that be true, some of the tables need new numbers.
If Dolby can ever achieve true whites, and get the rest of the color spectrum correct, I think it would be the best (passive) 3D system. As it stands, the color shift is the deal breaker for me. The hot setup would be a RealD system on a Barco PJ. Since most RealD systems in Denver are Christies, it will take some looking to find such a combination. If I find it I can do an apples to apples A/B. Until then, game point goes to RealD.
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Индустриальная табличка о сравнении 3D систем -- Spear -- 21.12.09@22:33 (Чит.: 298)