Monday, June 18, 2007
The Handheld Meter
Far from becoming obsolete, handheld exposure meters are at least as useful in the digital age as they are for film photography
Incident readings measure only the amount of light falling on the subject, negating background tonal influence and subject size relative to the image frame and meter pattern in use; thus, a white bird at 20 yards is exposed the same as one closer. Moreover, it doesn't matter whether the area behind the subject is white sky or green pasture. Incident meters precisely and consistently place exposure at the capture medium's midtone. As the exposure is set for a given quantity of light and ISO (EV), tonal values above and below the midtone will be rendered accurately. If you were to set your exposure using your in-camera reflected center-weighted or spot meter to photograph separately a white, gray and black piece of paper, the resulting images would appear identical—the same midtone gray. Using an incident meter, the papers would appear as viewed. In most situations, an incident reading is extremely accurate and records tones, colors and values correctly. When taking an incident reading, it's imperative that the reading be taken in the same light as that falling on the subject.
When using a digital SLR, I typically expose for the most important highlight, controlling subject shadow detail and contrast via flash. When metering for the most important highlight, aim the dome at the light source, as this is the area you want properly and consistently exposed. When no supplemental lighting is available, or the subject is too far for the supplemental lighting to be effective, you must expose for the primary subject (the dome faces the camera as you look at the subject), letting the foreground/background fall where it may on the tonal scale. Postproduction techniques using Levels, Curves and the Shadow/Highlight tool can be extremely beneficial in rendering accurately or modifying your shadow areas as you see fit.
In my experience, publishers prefer images with approximately a three-stop brightness ratio, as this is easier on the eye. When exposed at the incident meter recommendation, subjects that appear lighter than middle gray to your eye will appear lighter in the finished image. Subjects that are darker than middle gray will appear darker. Colors will be rendered accurately and highlight and shadow areas will fall naturally into place.
If the scene contrast is greater than that of the range of the image sensor, then the whites will lack detail and the darker areas will block up unless you compensate accordingly. The closing down of one ƒ-stop for whites and the opening up of the same for blacks is simply a matter of salting and peppering to taste. It's important to consider the image in totality, as compensating exposure will shift the tonal scale up or down much like a slide rule, giving up detail on one end of the scale to gain detail in the other.
You must pay attention to light intensity; be sure to take additional readings when the quantity of light falling on the scene changes. On heavily overcast days, the addition of +1⁄3 compensation will render a midtone subject a bit more lively (brighter); again, this is personal preference.
My personal meters of choice are the Sekonic L358 and L558R models; both offer weather/water resistance (my L358 floated in the Pacific Ocean overnight, washing up on the beach the next morning without any ill effects), retractable domes, 1⁄3-step increments (directly transposable into your camera without the need for estimation), Av and Tv modes, and flash metering. The L558R model additionally features a 1° parallax-free spot viewfinder with digital display and the lowest EV flash measurement available.
While in-camera meters are good tools and certainly beat using no meter at all, a handheld meter is still the preferred tool. Now that I'm shooting primarily with digital cameras, I find that I reach for my meter at least as much as when I was shooting film. Even with the impressive capabilities of RAW converters to correct for exposure inaccuracies, getting the exposure correct when you press the button always will result in the best image. Regardless of your metering method, the software program you choose to convert your RAW data has built-in curves that will have a great effect on the amount of detail initially previewed and rendered. This is readily apparent if you open the image in various programs without alteration. I highly recommend using one program and becoming as familiar with it as possible.
To see more of Charles Glatzer's photography, visit his website at www.shootthelight.com.
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