Shooting DV For Broadcast
It wasn't that long ago that some of the best documentary producers I worked with at Frontline (www.pbs.org/frontline) wouldn't abandon shooting on film because they were worried about the quality loss of shooting in video. Many of those same producers were the first to show up in our online rooms with DV originals.
Why did they change their tune? Because DV has become a valuable production format for the broadcast documentarian. It stretches the budgets of those users who normally shoot on higher-end formats, and makes possible documentaries that might not otherwise get made. Because of its less imposing presence, a DV camera lets a producer get into places he or she might not get access to with a broadcast camera and crew. And a DV camera gives the DP a smaller, lighter rig that can easily get shots that are difficult or impossible with a larger, heavier rig.
Now that we have this great tool in our production environment, what is happening with DV in post? How does it stack up against Betacam SP and Digital Betacam? What is it like to online and color-correct? What are the "dos and don'ts" of shooting DV for high-end documentaries? Let's take a look at how well DV comports itself in the broadcast postproduction pressure cooker.
We see a lot of DV in our Frontline suites these days. Six years ago, perhaps 1 percent of the footage we worked with was DV. These days up to a quarter of the materials coming through our facility are DV and many programs are shot exclusively in the format.
Some of the DV footage looks remarkable. Some of it looks lousy. In the best circumstances, DV intercuts seamlessly with Beta and D-Beta. When not handled properly, DV looks like their poor second cousin. We spend a lot of time correcting badly shot DV material.
If you are shooting on DV, advancing your knowledge ahead of the shoot pays significant dividends in postproduction. You will run into unavoidable problems during production; inevitably, you will be asking your post team to solve those problems. Do post a favor and don't give them more headaches than you must.
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| Automatic functions can be useful, but they can cause havoc that's expensive to fix in post. In this sequence shot with the camera's auto-iris (aperture) feature enabled, the shot's brightness shifts as a white car crosses the field of view. Avoid these shifts by manually setting the camera's iris. |
One of the most overlooked and productive things you can do as a filmmaker is to think through your entire production and postproduction process before you lens your first frame. Discuss with your production and postproduction team any questions or any special needs you may have. Don't assume anything. If you plan to acquire in widescreen or 24p, then you need to make sure you are not causing problems for your post house and your distribution network.
By and large, when I say "DV" in this article, I am referring to shooting on one of the prosumer DV camcorders, such as the Canon XL1 or the Sony PD150. If you are shooting with a larger DV rig, such as the Ikegami HL-DV7AW or the Sony DSR300 or DSR500 series, many of the same tenets apply. If you are shooting on a smaller consumer camcorder, the same tenets apply in spades.
One of the DV format's greatest assets is also its greatest shortcoming: its size. Because the cameras are smaller and can be easier to use than a larger rig, they are often handled unprofessionally. More producers are shooting footage themselves or using nonprofessional camera people to shoot. Although this can save money in production, that savings can be more than wiped out in post.
At my facility, we spend a large amount of time correcting mistakes made by taking the format too lightly. The key to shooting with a DV rig is treat it like it is a big rig.
What follows is basic advice for avoiding problems that make postproduction difficult and that limit the quality of your image. Although some of this advice may seem obvious, I've seen good, experienced producers make the very errors I detail. If you only work in post and don't shoot, then hand this article to a producer or client who will benefit from the advice.
Learn the camera's functions before you go out on a shoot. Nothing kills momentum faster than stopping everything to read the manual while you're shooting on a tight schedule. Know how to use your camera in manual mode. Manual focus. Manual exposure. Manual white-balance. Do not rely on the automatic functions unless you absolutely must. Let me repeat: Do not rely on the automatic functions unless you absolutely must. I see more scenes ruined by auto-iris and auto-white-balance than by virtually any other mistake.
These automatic functions can be useful, but more often than not, they spoil perfectly good scenes. For example, auto-iris will cause the average scene brightness to decrease and then increase again as a bright object passes through the scene. Likewise, auto-white-balance can shift the video's color if a strongly colored object enters into the field of view.
A typical example: We posted a documentary where the interview subject was occasionally gesturing with a yellow pad of paper. This caused two unintended reactions by the camera, which was set to automatic mode. First, each time the bright pad came into view, the iris closed slightly and then opened again when the pad dropped out of frame. Second, when the pad came into frame, the camera registered the bright yellow paper as the new white-balance reference point, shifting the overall color to a blue tint and then back again.
Each and every time this happened, we had to track the changes and try to compensate during color-correction. It took several hours to correct just that one interview. Although this is an extreme example, when cameras are set to automatic, we typically must perform extensive correction to several scenes in a one-hour program. That consumes time and money that would be far better spent in other ways. Not to mention what a thankless job it is to spend all of that time making the program merely viewable instead of beautiful.
Although these steps seem obvious, you'd be amazed how often we see footage without regard to the basic steps of preparing a camera to shoot. Always white-balance your camera for the lighting conditions in which you are shooting. For accurate results, carry a white-balance card with you and use it to balance the camera from near the center of the scene. When lighting conditions change, white-balance again. If you are using more than one camera, put up one white card and white-balance all cameras on the same card. Again, don't use your camera's auto-white-balance feature unless you have no other option.
After white-balancing your camera(s), the next most important thing to do is to lay down color bars and reference tone (typically 1 kHz). Thirty seconds at the head of every tape is usually adequate. It is important for the online editor or colorist to have those bars as a reference point for the online and color-correction session. Likewise, your editor and mixer will use the tone when they digitize the source tapes. It is a good idea to prestripe your tapes with bars and tone before you go out on a shoot so that you don't have to take the extra time in the field when tape changes need to be done quickly.
I also suggest to all of our shooters that they bring a chip chart with them on their two-camera shoots. The chart doesn't have to be expensive; you can buy a Kodak camera separation chart for about $18 from most rental and supply houses. Once a scene is lighted and the cameras are set up, the cameraperson shoots 30 seconds of chip chart from each camera. This makes camera matching in post a lot easier and faster.
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| Because this scene was shot with the camera's automatic white-balance feature enabled, the medium shot and the closeup don't match. This can be fixed in post, but will take time and may compromise the image. Control your scene's white levels in production by white-balancing to a white card. |
Why bother with both color bars and chip charts? Color bars represent the camera's internal baseline settings and therefore provide a good starting point for color-correction. Color bars can help a colorist get two cameras close, but he or she will have to do more tweaking to get them to match.
Chip charts go a step further and provide a specific reference point that takes into account the differences in the lenses, camera chips, and internal settings of each camera. Viewing the videotape of chip charts lets a colorist align the cameras more quickly and precisely.
One good tip: In post, always capture some of each camera's chip chart recording and make a sequence of all of them so the colorist can spend a few minutes getting baseline settings for each camera at the very beginning of the online session.
More and more productions are being shot in widescreen. Before you shoot an image wider than the standard 4:3 aspect ratio, find out what your distributor wants. If you don't yet have a distributor, think about what kind of production you are doing and decide if shooting widescreen makes sense. If you decide to shoot widescreen, do it the right way.
The internal widescreen setting on most prosumer cameras (sometimes called 16:9) crops the image at the chips. This results in a 30 percent reduction in image resolution. When using such cameras, it's far preferable to do an anamorphic conversion with a lens adapter. There are primarily two types of anamorphic adapters available. The lower-cost adapters, around $700, allow partial zooming through the adapter from full wide to approximately three-quarters zoomed in. The higher-cost adapters go for $2500 or more, but allow zooming through the full range of the lens.
Although it is tempting to shoot at 24 fps or another alternate frame rate to make your production "look like film," shooting at rates other than the NTSC standard 29.97 fps often backfires and causes headaches in postproduction. Frame rate decisions should be based on a multitude of factors from postproduction through distribution.
On rare occasions, such as with reenactments, a different frame rate can be used to good effect. Such changes can be easily created in post and don't limit other uses you might have for the footage. If you plan to shoot at a nonstandard frame rate, you should talk with your post team and your distributor about it before you go out and shoot. Better yet, shoot a test and get it posted, and then talk with everybody.
The DV format really suffers when pushed to its limits. Although DV cameras can typically shoot well in low-light conditions, the resulting image is usually quite flat. We call it the beige effect. When subjects are shot in poor lighting conditions-usually interiors where no supplemental lighting was employed-the result is that people, objects, plants, animals, and just about everything takes on a monotone beige look that is hard to inject color into during post finishing.
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| The drama of this shot is diminished by the overexposed whites on the subject's face. The image in those areas is clipped, and can't be recovered in post. A good shot made less good. |
Bring lights on your shoots and use them. You don't need a grip truck full of HMIs. A small amount of supplemental lighting can dramatically improve your material. At least bring along a reflector for times when lights are impractical.
On the other side of the coin, the reduced dynamic range of DV suffers big-time in high-contrast situations. The background blows out and the foreground loses detail. Try not to shoot interviews in front of windows or very bright backgrounds unless you can gel them or can put some serious light on your subject. Again, a folding reflector can be a low-cost lifesaver for high-contrast, subject-driven scenes.
Monitoring
Monitoring the image in many DV cameras can be the Achilles heel of a shoot. Be wary of using a camera's small flip-out LCD screen as a monitoring tool. It is common for a shooter or producer to report that the out-of-focus or overexposed material we are attempting to salvage looked great on the LCD screen. That screen is a fine tool for framing but a lousy tool for exposure and focus. Use the camera's viewfinder to set up and check your shots. Even better is using a high-quality monitor that has been set up with color bars. With a properly set up monitor, you will be able to verify your exposure and focus points with greater accuracy.
Learn how to use the zebra option on your viewfinder and flip-out LCD screen. When you see zebra stripes across the brightest parts of your image, those parts are approaching or hitting 100 IRE (depending on your camera's zebra options and settings). Look through your viewfinder and set your lens aperture (iris) to show zebras on only the peak luminance parts of your scene and the rest of the scene will usually fall into a comfort zone.
If you slightly underexpose your image, you can usually salvage information from the dark areas of your scene in post. However, if you overexpose and blow your scene out, there's no information to reclaim during post. Blown-out whites are the equivalent of clipping the signal when recording digital audio: Everything above the clip point is gone.
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| DV camera's viewfinder zebra feature let you know when white levels are about to blow out by showing diagonal stripes across portions of an image that are approaching or at 100 IRE. |
In the color-correction suite, we can't darken a clipped sky and have the clouds show up again. They are lost to the DV gods. Whereas on a tape that's exposed correctly, or slightly underexposed, we can add some luminance to the shadows or tweak the gamma curves to brighten dark areas of the scene.
Because of DV's limited dynamic range, there are times where you may need or want to overexpose part of your scene in order to expose another part properly. That's fine. Just be aware of what you are doing and do it on purpose.
Use a tripod or some other camera support as often as possible. I don't mean never shoot handheld. Handheld camera work definitely has its place. However, our experience has been that programs shot on DV have a much higher percentage of handheld material, and that handheld material often distracts the viewer more than intended. The DP should always be asking, "What camera technique best forwards this story at this point?" If an interview subject is talking while sitting in a chair, moving the camera around does not necessarily make the interview more interesting.
Audio
Bad audio really hurts a story and can render material unusable. I can't begin to count the number of times a producer or executive producer has said in a screening, "Isn't there anything we can do about that audio?"
An audience will forgive or ignore bad visuals more easily than they will poor audio. We need to cut around audio problems far more often than video problems because proper attention was not paid to the sound during field production.
Use microphones and use them properly. The mic on the camera is barely adequate for run-and-gun situations, but always comes up short otherwise. At a minimum, use hard-wired or wireless lavalier mics. A good mic on a boom pole is also useful. And all of the right equipment won't matter without the skill to use it correctly. Working with an experienced sound person on location can take care of all of your audio problems.
DV cameras are particularly prone to recording timecode breaks at camera restarts. You can avoid this in the field by checking the timecode when powering up at a new location or setting. If your camera has lost its bearings, it will usually show 00:00:00:00. On many cameras, if you rewind to the end of your previously recorded material and change back to camera mode, the timecode will pick up where you last left off.
Sometimes a break is unavoidable. Tapes with timecode breaks need to be logged, digitized, or imported properly during capture or digitization for editing. If they aren't, it will be impossible for an online editor or mixer to know which 00:01:24:07 is the one you wanted in the program. This creates scenarios where the amazing scene of the dictator denouncing his detractors gets inadvertently replaced by a b-roll shot of dogs exploring the intricacies of fire hydrants. When you do have a tape with timecode breaks, a good practice is to give each section of the tape a separate designation during import/digitization (tape 25a, 25b, 25c, for example). Also put a note on the tape, and additional notes in the timeline or EDL, to warn the next person who will have to deal with the problem.
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| Although DV cameras have impressive low-light specs, images shot in low light can look flat. A small light kit reflector can keep everything fram having the beige look, which is something that's hard to fix in post. |
At my facility, we spend so much time rescuing problem footage that it is a real pleasure when well-shot, well-produced material comes in the door. Putting these common sense practices into place will ensure that you get the most out of your shoot and the most out of your post team.
If you are thoroughly prepared before you go out and you execute well on the set, instead of wasting time and money in postproduction making your show look acceptable, you can spend both making your production look great.
Although some of the advice in this article is fairly conventional, you do not have to limit your production style to get great footage. There are numerous techniques and pieces of equipment out there that can add an extra dimension to your project. The key is to use them deliberately. Any decision you make on the set and in the edit room should be based primarily on a simple premise: Every decision must forward the story. Here are a couple ideas to consider.
Small DV cameras let you do things that are much harder to do with bigger cameras. We have seen inexpensive Steadicam-like devices used to great effect. When used appropriately, they can add a high-end feel to your piece for minimal cost.
We had a beautiful-looking documentary come through the shop a few years back that was shot entirely on DV. The DP shot long sweeping scenes with a Steadicam DV. The editor used the camera movement as a visual device to forward scenes and augment the flow from scene to scene.
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| Using even a simple tripod, such as the Bogen/Manfrotto 442 Carbon One with 501 head that Frontline uses in its DV kits, can keep viewers focused on content, not camera moves. |
Falling into the same category are a small dollies, jibs, and vehicle mounts. All of these tools can be found at most video rental houses. The key is to get a little time practicing with the device before going out on the shoot.
Varying frame rates can be very useful in setting a mood or a tone. Long time Frontline and American Experience producer Ben Loeterman has consistently and creatively used varying frame rates to set his reenactments apart from other material in his documentaries. On a recent Frontline called "Inside the Terror Network," he shot reenactments of Al Qaeda hijacker Mohammed Atta's life. The nonstandard frame rate helped distinguish the reenactment footage from actual footage of real events.
If you want to use nonstandard frame rates, or any in-camera effect, do some tests and cut the test footage together. See how you like the effect before you go out on your shoot.
Too often people experiment in the field and decide later they don't like the effect but they need the content. If you are not sure you like a particular in-camera effect, shoot it straight and add your effects in post.
Frontline's DV Package
While most producers who shoot for Frontline hire crews that have their own camera and sound packages, we maintain a full loaner DV package in both NTSC and PAL to help producers stretch their budgets. Here is what's in our kits.
Tim Mangini is the production manager of the PBS series Frontline and the director of its postproduction facility, OutPost.