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Schubin: 'Resolution Numbers are Approaching Meaninglessness'

1080i... 720p... 1080p... Ultra HD... QFHD... 3D... Help! What does it all mean? How much better can it get before the typical viewer no longer can discern what is "better" than what? HD Notebook asked longtime engineer, teacher, consultant, writer and all around DTV guru Mark Schubin to step back a moment for us, and add some perspective.

Although we can't stop progress, he says, if we're primarily interested in image quality, it's important to consider characteristics other than mere resolution.

"Consider demands on lenses." Schubin said. "NHK's Super Hi-Vision II (Ultra HD), as might be expected, makes the greatest demand because it needs 240 line pairs per millimeter at maximum resolution. And the Olympus Octavision (what others call QFHD) makes the second greatest demand at 200 lp/mm."

But the third greatest is not any of the extra high-resolution, digital cinematography cameras, Schubin said, "it's the whole range of 1/3-inch 1080-line HDTV cameras (HDV, Panasonic HVX200 in 1080 mode, and the Iconix in 1080 mode)." In fact, he says the lens demands of Super Hi-Vision are only a third greater than those of the 1/3-inch cameras, but the 1/3-inch cameras don't offer lenses as good.

Schubin says the new Red One camera, with more resolution than the Octavision makes fewer demands than an ordinary 2/3-inch HD camera, and the ARRI D20 and the Dalsa Origin make even less still.

"So you might actually get better sharpness out of one of those, than out of Super Hi-Vision -- since 'sharpness' is a psycho-visual sensation proportional to the square of the area under an MTF [modulation transfer function] curve, plotting contrast against resolution."

The whole idea of taking the entire system into account was Schubin's topic at the Digital Cinema Summit last month at NAB2006.

"If you were at the Sony press conference at NAB," he said, "you probably noticed the sudden drop in quality from the trailer for the new movie 'Click' (shot with the Panavision Genesis) to XDCAM HD, despite the fact that both were 1080-line HD. Resolution numbers are approaching meaninglessness."