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Lighting for Streaming
- Categorized in: Lighting for streaming
Without question, lighting is the single most important determinant of streaming quality. Shoot a well lit scene with a consumer camcorder, or a poorly lit scene with the latest HD wonder with 2/3” CCDs, and the consumer camcorder will win every time. Fortunately, it’s just not that hard to get lighting right, which is what I describe in this article.
I’ll start with a brief look at the history of lighting, then describe the optimal procedures for lighting for streaming. I’ll conclude with a look at how to use your camcorder to determine when you’ve got sufficient lighting.
Consider lighting from the perspective of early TV producers. The television screen was a small, flat, fuzzy medium, through which producers had to create depth, to model the character’s faces and separate them from the background. To accomplish this, they used three point lighting, as shown in Figure 1.
Figure 1.The three lighting locations for three point lighting.
As you would expect, three point lighting uses three lights. The back light shines down on the subject’s head, separating them from the background. The key light, on the left in Figure 1, is the primary light source, and shines directly on the subject’s face. The fill light is to minimize shadows, and usually contains about ½ the intensity of the Key light. As shown in the figure, the key and fill lights are positioned at about a 45% angle from the direction the subject is facing, and placed above the subject, so that they project down at about a 45% angle.
The result is a face with shadows, as shown in Figure 2, a frame from a Hewlett Packard case study streaming video where they interviewed an executive from Warner Brothers. Here the key light ison the subject’s right, the brighter side, with a softer fill light minimizing the shadows. You can also see light shining on the back of the subject’s head, evidence of the back light.
Figure 2.Three point lighting used in an HP case study.
Though used by HP to good effect in this video, traditional three point lighting presents several problems, both in the television environment and for streaming. On TV news shows, anchors tend to move too much to sustain three point lighting, which is challenging to maintain when the subject is turning around or standing up and sitting down. It’s very challenging to produce three point lighting when you have multiple subjects on stage, especially if located close together.
Finally, three point lighting requires intense hard lights like incandescent, which are harsh on the eyes and hot. For these reasons, most studios have switched to banks of softer fluorescent lights that light both sides of the face equally, producing overall flat lighting. In fact, In my survey of 13 news oriented shows that post streaming video to the web, including CNN, CBS, ABC and ESPN, none used three point lighting. Instead, all moved to entirely flat lighting, as shown in Figure 2.
Figure 3.Flat lighting used by ABC news.
In fact, the only time you really see three point lighting on news-oriented television anymore is on dramatic shows like 60 Minutes. It’s almost solely used for totally static interviews, since it’s almost impossible to sustain when the subject is moving.
In the streaming environment, the shadows created by three point lighting are also very hard to compress at good quality, especially at low bit rates. For this reason, for day to day training and announcement type videos, most streaming producers have shifted to flat lighting as well.
Even if you don’t have the budget for banks of fluorescent lights, producing flat lighting is relatively simple. Just convert your fill light to a key light, and light the subject evenly from both sides. If you’re using harsh incandescent lighting, soften it with gels or diffusion filters, or bounce it off bounce cards or Flex Fills. Don’t forget the back lighting; it’s still critically important to separate the speaker from the background.
Don’t discard three point lighting altogether; it’s great for interviews, where it’s wonderfully complementary to most faces. The dramatic look it produces may not be appropriate for the director of finance announcing a new expense report policy, however, and it’s risky for low bit rate videos.