Camera shading basics
Dec 1, 2008 12:00 PM, By Tony Manard
Making your cameras match is both art and science.
Be careful about bright items like white shirts blowing out or going above 100 percent video and clipping. If this happens, you may have to adjust the knee circuitry's threshold. The knee circuit decreases amplification at levels approaching 100 percent video in much the same way as an audio compressor works.
If you are shading in a controlled lighting situation like a studio, try to adjust the light levels so that your iris is around F stop 2.8. This will give you range to adjust up or down without having to use filters or gain. If, on the other hand, you are shooting in a dark theatre or at an outdoor event, there are a host of tools in the modern camera to adjust for this.
Most cameras now come with a basic filter wheel built in. Neutral density filters reduce luminance levels without affecting color temperature. Other filters account for differences in color temperature for various light sources such as sunlight or fluorescents.
Gain can be applied for low light situations, but should be used sparingly because it adds noise to the signal. Also be aware that many CCU controllers allow the operator to set the sweep range and sensitivity of the iris control.
In a studio setting where only subtle adjustments are being made, limited range and sensitivity of the controls can be helpful. In a less controlled lighting situation, maximum sensitivity and range of adjustment may be called for.
Save your settings
Modern cameras also offer the ability to save individual setups or scenes. The saved file will include white balance information for a given setup. A good example of this would be for an evening baseball game where the cameras start out on a filter for sunlight that is switched out as the sun goes down; a saved setup can be recalled that includes the white balance for the camera without the filter so it does not have to be balanced again.
Another handy function of saved setups is for skin detail. Many modern cameras allow detail for a given hue to be decreased without affecting other elements of the picture. Skin details for individuals can be saved and recalled at will. Another consideration is using the preset white balance that is set in almost all cameras at the factory. In cases where cameras are matching models from the same manufacturer, this can be a viable option for lighting situations that include a number of different colored scenes where getting a good white balance across the spectrum is not practical.
In the end, camera shading is almost as much art as science. Dramatic use of color and black levels can create a look that is appropriate for the production. When time allows, don't be afraid to explore the camera's settings to see what is there.
Many modern cameras include presets that mimic different looks and film emulsions, affording a custom look with a minimum amount of guesswork. Be sure to save a standard setup that you can recall if things get too far out of whack. The possibilities are almost limitless.
Tony Manard, CBTE, is a broadcast engineer based in Memphis, TN.
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