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Tuesday, September 28, 2010

The ExpoDisc by ExpoImaging functions like a gray card, but is easier and faster to use.

“Let’s just fix it in post” is a statement often heard on sets these days. With nearly all 35mm films going to DI and most high-end digital systems capturing in RAW, a cinematographer will take the occasional shortcut, knowing full well that he or she can make fine adjustments in post.

But what if you’re shooting with a non-RAW codec or a highly compressed codec like MPEG-4? HD DSLRs like the Canon EOS 5D Mark II or camcorders like the Sony NXCAM record footage using the MPEG-4/H.264 format, which has significantly lower bit rates and less color information than high-end professional systems. Nor can they capture RAW files like the RED ONE, which gives you greater image control over white balance, gamma or other image settings in postproduction. Because of the high compression of MPEG-4, most filmmakers working with HD DSLRs are trying to capture their images as close to a finished look as possible, even with the transcoding of files to larger, more stable codecs like Apple’s ProRes or Avid’s DNxHD. There are a few cinematographers who like to “bake the look” into their images so a director or producer can’t change his or her look down the postproduction chain, but it’s safe to say that most cinematographers would rather have the option of making changes later in post if need be.

For HD DSLR shooters, to tone down crushed blacks and blown-out highlights, many 5D Mark II and 7D users are using Picture Styles in the camera’s menu system, using a “Neutral” rather than “Standard” picture style and dialing down their saturation and contrast levels to generate a more flat or neutral look. This might be best described as a poor man’s RAW look in 8-bit video.

There also are a few tools that help filmmakers capture more of an in-camera “finished” look. To capture the correct exposure, Marshall Electronics has a terrific feature installed in its LCD monitors called False Color that enables proper exposure without the use of external test equipment. Due to the HD DSLR’s small built-in LCD, it can be difficult to judge your image, especially exposure. With False Color, by adhering to a simple color chart, the on-screen image will read out green and/or pink when the camera subject is exposed correctly.

With HD DSLRs, obtaining proper white balance is another difficult challenge in capturing your look in camera. The human eye easily can read the color temperature of a light source, but a digital imager has more difficulty, especially if you’re using an AWB (auto white balance) feature. For HD DSLR shooters, one of the simplest, yet effective products to capture your correct white-balance setting is the ExpoDisc by ExpoImaging, which functions like a traditional gray card, but is easier to use. Offered in various filter sizes, the ExpoDisc is a simple white disc that snaps on the front of your lens. After you determine your exposure and shutter speed, aim the camera with the ExpoDisc on your lens toward the light source that‘s lighting your subject. Take a test shot, which then will display a blank grayish screen. Return to your menu and reset your white-balance setting to custom white balance to your newly shot image with the ExpoDisc. The same color temperature of light lighting your subject will pass through the ExpoDisc to your camera’s imaging sensor, giving you the correct color temperature. It’s a much simpler process and frees up both hands rather than holding out a gray card or having an assistant do so.

Just remember that with H.264 files, the less postproduction color correction work you do, the better off you’ll be later on.

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