Check Your Meter

The intern stared at me incredulously with owlish eyes as I pulled the light meter from its holster on my belt. Though she remained silent, she seemed to be saying to herself, “What's this old fool doing with that ancient instrument? This is video; you don't need a light meter.”

Oh, how innocent and naïve are the young.

It's true that in video you can set your exposure automatically, or by using built-in camera zebras. Or if you really want to be accurate, you can haul around a waveform monitor. The intern was right that in video you don't technically need an exposure meter to set the f/stop on the lens.

Back in the days when I was shooting film, a DP couldn't live without his meters, although I did get pretty good at guessing the correct exposure by holding up my thumb. (There was an old joke among cinematographers that the whole world was f/5.6.)

When I made the transition from film to video, I, too, left my exposure meter at home. Until one day when the magnificent lighting director at WCVB-TV in Boston, Wayne Smith, convinced me that this was a stupid idea.

A light meter is invaluable in setting a multitude of exposure values within a scene. If the whole scene has the same exposure value, it will appear flat, bland, and uninteresting — and it could be your last job. Of course, you can do this through the lens, but it's much more accurate with a light meter. The videographer determines what F stop he wants to shoot the scene at, depending on depth of field anticipated, amount of lighting instruments available, air conditioning, electricity on the set, etc., and goes about setting light values accordingly.

In the United States, light meters measure either foot candles or f/stops — sometimes both. One foot candle equals the total intensity of light that falls upon a 1-square-foot surface that is placed 1ft. away from a point source of light that equals 1 candle power. Each higher number on the aperture ring of the lens is equal to approximately double the foot candles.

You can increase the amount of light falling on a subject by using a larger instrument, focusing the lens of that light source or by moving the light closer. It also depends on the reflective surface of the subject being lit. A dark object won't appear as bright as a white object. (Duh.)

So, after you've chosen the exposure for the main subject of the scene, you can spend your time moving light around, adding instruments or scrimming them down to add interest to the scene.

There are basically two types of light meters. Incident meters measure the light directly from the source. Reflective or spot meters measure the light reflected back from the object being photographed. Most modern meters give you a choice between either incident or reflective.

It will take some practice to learn how to use your meters effectively. Luckily, there's a ton of useful “how-to” information on the Internet and from manufacturers.

Much like using the auto exposure built into your camera, you have to know not to be fooled by the penguin in the snow. But once you get the hang of it, you'll be able to paint with light creatively so your scenes will come alive. And think about how impressed your clients will be as you stroll around the studio with a light meter buckled to your belt like Gary Cooper in High Noon.

Let me know your tips at
billmillerfilm.com.