DPs debate hi-def techniques, drawbacks
LOS ANGELES
Advocates of high-definition video marvel at its vast improvement over the NTSC standard. They point out the futility of comparing HD to film, noting that the audience's eyes either can't tell the difference or adjust to these differences as the entertainment progresses. And some even insist that HD stands on its own merits and therefore should not have to mimic film.
Directors and DPs familiar with both technologies expressed all these viewpoints on a panel called "High-Definition Filmmaking/Common Problems and Problem Solving," hosted by HDFest.
Despite the accolades, talk focused on HD's drawbacks vis-à-vis film and how to compensate for them.
"There's no tape format that can handle full -- resolution hi -- def without some level of compression," DP Christopher Lockett told TV Technology. Lockett has used the Sony HDW-F900 (CineAlta) and Panasonic 27F (VariCam) as well as 35mm film cameras. "The signs are all there that tape will go away, replaced by some sort of disk system or pure data recorder."
Until that happens, crews will have to deal with limited dynamic range, radical TV colors and timecodes broken with each downconversion.
FINDING THE COLOR
To minimize dynamic range limitations, Lockett tests lighting options by shooting slides on a 35mm SLR camera in full manual mode using a light meter, because slides have a characteristic curve nearly identical to HD video. Using a slide projector, the slides would also give the camera operator tips for shooting for the big screen.
But, he said, even the best efforts to maximize an HD signal fall short in capturing, for example, a frothy, sunlit waterfall cascading past gray granite onto wet black rock in shadow. The scene would be robbed of impact, he concluded.
Haloing is another side effect of HD circuitry.
"What it's doing to make the apparent sharpness is creating an artificial edge around something -- which is fine on a 32 -- inch monitor," explained Ken Garff, DP and digital image specialist at In24p Creative, who has also used the HDW-F900 and 27F. "But if you blow that up to a 40-foot screen, that edge can be six inches wide."
As for adjusting HD's radical TV colors to film's nuances, Garff said you can design the menus within the camera to emulate film stock or do color corrections in post production.
Color correction in playback or post is preferred, said Thomas J. Ryan, post-production talent and director of HD feature "Wonderland Funk," who heads Anything But Hollywood production company and owns an HDW-F900 and a G4 Final Cut Pro Editing System.
"If I clip or crash [during production], the information in that area is lost forever," he said. "Never record it that way. You can still do all those things when you play the tape back. And, if I've protected myself, when I get to post production I can create any look I want with a DaVinci 2K color correcting system."
Coordinating timecode is crucial because the tapes used in production and post production vary in speed and length.
Ryan advocated having a 10 -- second pre -- roll on master tapes, accurate smart slates, timecodes of all downconverted tapes slaved to the master, and visible windows that reflect timecode for the master (23.98PsF frame) and downconverted (29.97 frame) tapes. And when you digitize the offline edit, make sure the function on your editing system that lets you "abort capture and timecode breaks" is on; otherwise the EDL will never match the master.
He also advised consulting a post-production facility early on and hiring a specialist to set up monitor and camera levels.
TARGETING THE DEPTHS
HD's depth of field is also problematic. The tiny CCD chip provides a much smaller target for capturing an image than 35mm film does, which translates into much more detail in the background. This makes it harder to determine spatial relationships in a shot and to focus on what the director deems important.
Since depth of field is determined by target size and the focal length of a lens, cinematographers are clamoring for adapters that increase the target size or lenses that let HD cameras shoot as wide open as possible.
"Zeiss DigiPrimes (HD lenses) get us almost back to 35mm depth of field," said Garff, who noted similar offerings by Fujinon and Canon. "P+S Technik created a lens adapter that allows the cinematographer to use all the 35mm lenses."
He was referring to the PRO35 Digital Image Converter, which actually contains a piece of glass that acts as a larger proxy target for the HD camera than it would otherwise have, Garff explained. "By the fact that it's the same size as a piece of film, it gives us back all the characteristics of film depth of field and field of view," he said.
A Canadian company, Dalsa Corp., also promises to improve depth of field-and resolution, said DP Thaddeus Wadleigh.
"Dalsa is purporting to get an image size that is comparable to the amount you're going to find on 35mm," said Wadleigh. "And the resolution is two to three times what we're capturing on 1080i-actually taking it up to 3K or 4K."
But for Wadleigh the biggest improvement for hands-on performance is the camera's viewfinder.
"Because it's optical, you see what comes through the lens [versus the tiny black-and-white CRT image you see with other video cameras]," he explained. "And you can see what's outside the actual frame-you have a frame line." Frame lines are a helpful alert to boom operators or other distractions that threaten to ruin a shot.
He's also hopeful about a new and improved HD camera from Lockheed Martin.
Wadleigh has not, as yet, sampled Dalsa's Origin camera. He used the HDW-F900 to shoot an upcoming feature called "Loco Love" and a 30-second HD promo for TNN's re-launch of "Ultimate Revenge," a TV series shot on the NTSC standard.
"They ended up transferring everything to Beta SP and cut it in an analog world," he noted of the TNN promo.
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