Tuesday, June 5, 2007
The Case For A Light Meter
There's no substitute for getting the right exposure, and there's no better tool for that than a precision handheld meter
Light meters fall into two general categories: reflective and incident. Your in-camera meter is a reflective meter in that it measures the light reflecting off the scene. Modern digital SLRs have incredibly advanced in-camera meters that are coupled with high-tech image-processing algorithms to establish the best exposure. Like any tool, though, they're not perfect for every job. For example, while most have a spot mode, the size of that spot varies depending upon the lens that's mounted, and you usually can't see the parameters of the spot area in the viewfinder. You might think you're only measuring the light on a door panel, when in reality you're reading the entire door and part of the walls.
Having a good handheld reflective meter with a spot capability avoids the drawbacks of the in-camera meter. These devices are pure simplicity in terms of what they do. All reflective light meters when set for normal exposure will render the subject as 18%, or middle gray. That's it. That's all a reflective meter does. By moving the spot area around within the frame, you can precisely read specific tones and, more importantly, you can read the relationships between the tones within the scene. Anytime you're using lighting gear, the need to measure tonal relationships is paramount.
The other class of handheld meters is the incident meter. Instantly recognizable by its white, ping-pong ball-like hemisphere, an incident meter measures the light falling on it. When the reading is taken from the subject's location, an incident meter will accurately render an exposure free of any variance from colors within the scene. Let's say you light a subject in a studio, getting everything perfect. You can use the incident meter to establish the perfect exposure for the lit scene. What you can't do with an incident meter is read the relationships between the tones within the scene.
The strength of the incident meter is its ability to provide a reading that will result in the accurate rendition of color, tonality and contrast within the scene, regardless of varying levels of reflectivity. A reflective meter is susceptible to false readings based upon the surface reflectivity of the subject, while the incident meter is immune. Using the incident meter, colors are correct, and highlights and shadows fall naturally into place.
So what's the best kind of meter to have? The answer is simple—both. A reflective meter is ideal for certain situations while an incident meter is the preferred tool for others. Old-school studio photographers frequently use both every time they set up a shot. The reflective spot meter gets the call for seeing the relationships between tones, in addition to making sure that highlight and shadow detail falls within the range of the sensor; then the incident meter comes in to confirm the exact exposure setting.
In the torrid pace of advancing technology, there have been casualties among handheld meter manufacturers. The recent announcement that Konica Minolta is leaving the photography business led us to wonder about the Autometer product line. The response wasn't encouraging, and it seems the Autometers will continue to be serviced, but no longer produced. Sekonic remains a major player in the meter business, and it continues to develop professional-caliber products that take into account the needs of modern digital shooters. Gossen also manufactures a wide range of instruments that are ideal for digital photography.
The need for a light meter hasn't diminished in the slightest with the advent of digital cameras. No amount of work in the computer will save a flawed exposure. Your ultimate image will only be as good as the exposure when it was taken. Having a light meter in your bag remains an indispensable tool for every photographer.
Page 2 of 2