DSC CamAlign is Key to HD Production

By Scott Billups
Filmmaker/Director of Photography
PixelMonger
LOS ANGELES

Everywhere you look in L.A. there are productions using HD, and all of us who preach the gospel of technological innovation are being asked to put up or shut up.  

For years, 60i was the leading postproduction standard and now, almost overnight, we're seeing a quantum shift to 1080/24p.

HD is rapidly becoming the digital production standard that we've all been waiting for.  Sure it still has a few drawbacks.  Acquisition equipment is still rather pricey, and as usual, the manufacturers are are still trying to play the standards shell game.

The truly amazing thing is that the industry seems to be driving the manufacturers for a change.  Two years ago, you'd be hard-pressed to even find a player that could pump out any flavor of 24p.  Now, I run out of fingers and toes when I try to count all the television shows that are switching over.

The driving force for the big shift to HD production is quality at a reasonable cost.  The CamAlign camera chart alignment system from DSC Laboratories helps us keep the quality high and the costs controlled.  

The sudden acceptance of HD isn't occurring just at the high-end post-houses either.  Just about any PC or Macintosh user can slap a card into a home computer and start banging around HD video.  One example is Apple's new FinalCut ProHD, which offers up an editorial environment that is every bit as professionally endowed as its far, far more expensive kin.

A LITTLE CONFUSION
You'd think that with the acceptance of HD that there'd be more than a little confusion ... and there is.  The single most common mistake I see in HD production is calibration.

I'm guessing the culprit is twofold.  On one side you've got the film shooters who are accustomed to an acquisition medium that has enormous latitude.  The vast bulk of film directors of photography shoot down the middle of the road and figure that they'll have time to tweak in postproduction. 

On the flip side of that equation are the videographers who assume that since they're now shooting on HD the resolution will give them a wider FIIP (Fix-It-In-Post) ratio.

Both are right to some extent but, unlike film, where the inherent latitude can accommodate a multitude of sins, HD is a finite commodity.  You shouldn't think of HD as digital film but rather as very good DigiBeta.  The HD project destined for film distribution needs to have a flatter gamma curve than a project destined for digital projection.

The HD project destined for broadcast generally uses a "safe" factory preset that produces a lower density signal with greater latitude.

Whichever distribution mechanism you're shooting for, the secret to good HD is quite simply a waveform monitor and a good set of charts.

CALIBRATION MEANS QUALITY
Keep in mind that every time you recalibrate or re-time an HD shot in postproduction, you're decreasing your signal's inherent quality.  You're throwing away data that it desperately needs.

For feature projects where multiple cameras are in play, it is customary to use the "video village" configuration, which takes the SDI and RGB out of the two cameras and then feeds the the images into an HD waveform monitor.  The monitor is then used to switch the A and B signals into the quality control monitor.  

For smaller shoots, pickups, remote locations and inserts, I use an AJA converter to get the HD SDI signal into my laptop computer where I use the waveform and vectorscope functions in Apple's FinalCut Pro to adjust the camera's parameters to match the rest of the footage.

Every HD shoot I've been on has used the CamAlign colorbar/grayscale chart from DSC Labs.  This wide dynamic range chip-chart seems to be the standard in L.A. - it's very precise and provides optimum colorimetry and density calibration.  Mounted on 1/16-inch aircraft aluminum with a protective surface and edging, CamAligns are tough and even washable.

In a recent HD for film project we were shooting with two Sony F900 HDCAM cameras - one with the Panavision Primo Digital lens system and the other with a Canon HD lens.

The inherent color temperature difference between the  two lenses was significant, so we spent the time and energy to chart and calibrate the two cameras at every setup.  Otherwise, we would have sacrificed as much as 6 percent of our signal's already limited color space in postproduction.

In my opinion, CamAlign is the perfect accessory for serious DV moviemakers.  Careful adherence to a common set of calibrated references is critical for maintaining image quality on any HD project.  And image quality is the reason we went to HD in the first place.

Scott Billups is a SMPTE member and award-winning director, cinematographer and VFX supervisor.  He can be reached through his company's Web site at www.pixelmonger.com.  Scott recently published a book called "Digital Moviemaking: A Butt-Kicking Pixel Twisting Vision of the Digital Future and How to Make Your Next Movie on Your Credit Card."

For more information, contact DSC Laboratories: (905) 673-3211, www.dsclabs.com.

(Reprinted with the permission of TV Technology)