Magazine article American Cinematographer

Reflections: Electronic Imagery

Magazine article American Cinematographer

Reflections: Electronic Imagery

Article excerpt

The more recent technical advances in broadcast video cameras have changed the way much of the production industry views electronic imagery. From a cinematographer's point of view, the primary drawbacks of shooting on tape exist in the limited latitude of the electronic image, and within the confines of the zoom lenses that accompany nearly all of the available cameras.

Regarding image quality and camera sensitivity, current video cameras are capable of producing crisp, clean imagery, even in low light levels. When treated properly, a well-crafted video image can begin to show some of the qualities of an image recorded on film. Videotape now can be considered a viable option for commercial and high-end corporate productions. There are many pros and cons to shooting on videotape rather than film, of course. But with the current economic situation and tightening production industry budgets, the cost savings of videotape are allowing many productions to be completed that otherwise might have been shelved.

With the rise in video production for high-end projects, it is in the interest of the director of photography to understand some of the advantages and drawbacks of video cameras. One of the obvious concerns with video is the reduction in image latitude. A safe assumption for video image latitude is approximately 5 f-stops from black with detail to white with detail. Considering the expanded latitude of some of the new films, the limited latitude of the video image can demand a thorough knowledge of light manipulation to produce the desired results on tape. With reflective objects, such as the razor in the accompanying image, lighting becomes even more critical because we are dealing with the compression of a highlight area to fit within the 5-stop range.

For this image, the use of a waveform monitor was critical during the production. The waveform is the electronic equivalent of the light meter, and an understanding of the instrument and how it can aid you in Grafting an image is essential to high-end video production. Forthis shot, the basic lighting was done by eye, but the manipulation of the brightness of the primary specular highlight (mirrored image of the light source) on the chrome surface of the razor was aided by the use of a waveform. With film, highlight areas can be overexposed by several stops and still retain detail in the final image. But with videotape, the toe and shoulder of the image clip off quickly and dramatically, and all detail is lost in areas under- and overexposed.

I believe that, contrary to popular opinion, an image on tape can and should, when appropriate, have small areas that exceed 100% on a waveform. But the areas must be small in the image frame. For instance, a large background window in a scene will not hold well on tape if the window area is well above the 100% level on a waveform. Because of the electronic nature of the image, a blown-out window just doesn't have the same feeling on tape as on film. I've been told by a trusted video engineer that white with detail registers at approximately 92% on a waveform, and any area above that loses detail quickly. If we work with the idea that every 20% on the waveform represents approximately one f-stop in our 5-stop range, that only allows for one-half stop of latitude for white without detail before the image is electronically clipped off.

Another disadvantage of video cameras is working with the zoom lens that is a standard fixture. Wide-angle lenses often are used for tabletop work, but the close-focus distance for most video zoom lenses is approximately 2.5 feet, which forces the cinematographer to shoot at a longer focal length than may be preferred. Super-wide-angle zoom lenses with close focus distances of less than 1 footare available for rent. This particular image of the razor was designed to be shot with a medium focal length lens. With the zoom lens set at approximately 28mm (80-85mm equivalent in 35mm cine), the focal distance was set at 2. …

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