Basic Training: Looking for Light (page 2)

Gain allows you to electronically boost video. Check your camera's manual to find out if it has a manual gain control. As you increase gain, you will also increase signal noise, which can reduce the quality of the recorded image dramatically. Like everything else, it is a trade-off.

Some cameras are made for convenience; others are made for effect. It stands to reason that a camcorder you can fit in your pocket won't have the features of a larger contemporary. This is especially true in terms of aperture size. Small cameras, designed for maximum portability, have smaller lenses and narrower apertures. Some have a relatively large aperture at the wide end of the zoom range that gets smaller and smaller as you zoom in. To maintain a wide aperture throughout the length of a zoom requires big glass.

There are really only two ways to capture an image in low light. One is "gathering" light, which means dealing with the existing illumination through wider apertures and slower shutter speeds. The other way is throwing out more light. However, in certain situations (e.g., shooting in an Army foxhole or movie theater), turning on a light can be a bad idea conceptually. Luckily though, there are lights that cameras can see that people can't. So-called "night vision" cameras use LEDs to illuminate the scene with infrared light which is invisible to the human eye. Then, the camera's CCD, which is sensitive to IR, records the image. Usually in a weird-looking green monochrome. Because of this, IR is usually only useful for special situations like police stakeouts, where the image quality is secondary to what's on the image. These cameras can record video in complete darkness.

Either Mohammed goes to the mountain, or the mountain goes to Mohammed. To shoot in low light, you need to either put light on your subject or get more light off of your subject. Putting more light on your subject could involve adding sources such as flashlights or candles, opening blinds, moving your subjects to a location where there is more light or even adding invisible infrared light. Getting more light from your subject might mean a wider f-stop, higher electronic gain, a slower shutter speed, re-framing to avoid confusing your internal metering, or upgrading your camera. Many times you'll find yourself balancing between both techniques to get the best results.

Kyle Cassidy is a visual artist who writes extensively about technology.

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