Advice on how to handle more depth of field, variable frame rates and sync issues
Get A Very Precise Monitor, Then Watch It Like A Hawk
Robert Primes, ASC
Recent HD Projects: Baadasssss, MDs (TV Series), Forgotten Valor
We’ve learned to do tests with film, study a film stock’s latitude, use an exposure meter, make a very educated estimate as to how film will see things and eventually light by our instincts. There’s a safety cushion with film in that you can almost always overexpose a little and print down. That’s not true of HD, which has excellent shadow detail but much less overexposure latitude.
To make accurate calls, I hook-up the camera to a very precise monitor, generally a 24-inch Sony, and keep it meticulously calibrated in a very dark area. Instead of using an exposure meter, I prefer to evaluate the picture on the monitor so I can instantly see exactly how it looks- where exposure tones are falling, exactly the type of effect that filters and color gels are having. I can alter it immediately and can feel the gestalt and power of the near-completed image.
The paintbox, which is tethered to the camera and similarly to the monitor, allows me to ride exposure, black level, gamma, some highlight control and some color control in real time on the fly. It lets me tweak and compensate for a great deal of the missing highlight exposure latitude.
With HD (or 16mm) there’s much more depth of field at a given image size, angle of view and aperture than with 35mm film. While this can certainly be beneficial when you need a lot of depth, the danger is cluttering up your frame with sharp but insignificant distractions. It is much harder to use selective focus to lead the viewer’s eye to a subject. The mitigating factor is that the HD lenses are very fast, typically T1.9-1.5. They are generally optimized for shooting wide open. By using ND filters including the ones built into the cameras, and shooting at very wide apertures (which allows the use of less light), the so-called "problem" pretty much goes away. The depth of focus becomes really critical though, so watch the big reference monitor like a hawk for drifting back-focus.
You Should Still Worry About Keeping Your Audio And Video In-sync
National Mobile Television/Somerville, NJ
Recent HD Projects: Design HD4, HD6, HD7 and HD8 high-definition trucks
Today there is no need for an HD production to look any different than a top-of-the line SD production. Everything from production switchers and routers, to DDRs and DVEs has transitioned to HD. And while 16:9 framing does allow (or even dictate) some changes in camera positioning, current camera positions at the vast majority of venues are serviceable and the creative community has adapted quickly. Additionally, the development of triax-based multi-format HD cameras by all major manufacturers has eliminated the logistics of installing a new cable infrastructure at every venue. While it is true that fiber is the gold standard for video transport of all types, especially HD, the camera systems available today produce exceptional quality images using existing copper cable.
So, if it really is so easy to produce HD, why is there still so much trepidation? It turns out that there are still things to worry about, just not the things we were worried about in the beginning. There are a few major areas to be focused on. Audio-to-video synchronization (particularly when using analog audio production), video and system timing, reference types and paths, camera viewfinder quality and cable distance and condition (for triax cameras).
Director, DTV development and media planning
Recent HD Projects: The 76th Annual Academy Awards, Monday Night Football, The State of the Union Address
The first thing that production people learn when they start to work in HD is that focus is so much more critical. Typically these cameras [ABC uses Grass Valley LDK 6000 mk II WorldCams] are somewhat less sensitive than current SD cameras. This results in a shallower plane of focus, causing the depth of field to be somewhat narrower than what they’re used to. This really becomes apparent on action coming toward the camera. You find out right away who your better camera people are.
Another thing is managing the aspect ratio. With these productions you’re shooting for the most part all in HD and the final product is broadcast in HD and SD. But because the audience is still 95 percent SD, the directors, producers and production people need to concentrate on the 4:3 aspect ratio. That’s why just about every monitor on these trucks is 4:3, with typically only one or two that are 16:9. The camera people still have to frame for 4:3. But because the 4:3 is center-cut from 16:9, the camera people also have to worry about what’s there in the 16:9 frame to make sure they don’t catch something indecent that is unnoticed in the truck.
Shoot Alternate Takes For Slo-mo
Dark Spark Media/Royal Oak, MI
Recent HD Projects: "Year of the Car" for Ford, "A Road to a Legend" for Chevrolet
Initially we were in love with shooting 24p, but eventually with the good came some bad.
The HD image coupled with the 3:2 pull down gave a very pleasing look. And the VariCam’s ability to shoot at low frame rates (like 6 fps) let us produce shots never possible before in video. But headaches started in post when we slowed-down 24p footage. It gets a jerky effect on screen mostly due to the 3:2 pulldown. Panasonic does make a frame rate conversion device, the AJ FRC27, but we decided to experiment with slow motion on our Avid DS HD edit system instead. If material is shot at 60fps and posted in HD, the DS system does a nice job of time-warping the shots to give quality slow motion. We also found that if you are doing a SD edit with downconverted HD material, you can acquire at 30 fps and get nice slow motion.
Shooting in alternate frame rates does require a little extra pre-production though. If you shoot in 24p you will probably not be able to slow it down in post. You can get around this by shooting alternate takes in 30 or 60p. To make your editor’s life easier, use an ordinary film slate at the head of each shot and designate the frame rate you’re shooting.