Today’s Post by Joe Farace
These days DSLRs and mirrorless cameras offer multiple methods for metering how that light is reflected in a scene. The most common methods include:
Multi-segment: Sometimes called multi-zone metering, this system, divides the viewfinder into multiple (number varies by camera) segments. The camera’s processor determines overall lighting level, including front and back lighting, and sometimes the color in each portion and compares it to a database of similar scenes to determine exposure. Some systems integrate the data from the focusing point used, subject size and distance. For many cameras this is the default settings and works fine for the average photograph.
How I made this shot: This photograph of the Acapulco Yacht Club was made using a Canon EOS 5D’s Evaluative metering system that link to the camera’s nine autofocus points. The Program mode exposure was 1/125 sec and f/5.6 at ISO 320.
Center-weighted: The camera’s metering measurement is weighted (75-80%) toward the center of the focusing screen and was an improvement over early built-in meters that took an average of all light values in the screen and were heavily influenced by extremely dark or light areas on the edges and corners. You should use Center-weighted metering when the main subject covers a large portion of your photo but this mode does not compensate for backlit scenes. The next one does…
Spot metering: Brightness is only measured within a limited area (often one to three percent of the frame) within a circle at the center of the focusing screen. You can use this type of metering for backlit scenes by placing the sport on the subject and not the background. Photographing a performer or speaker on stage that’s illuminated by a spotlight is a good example. To be properly exposed, the secret of using spot metering is to place the spot where you want it, always remembering the metering system’s limitations.
How I made this shot: New York Fashion Week runway’s are lit for video coverage and no flash is permitted for the model’s safety. Spot metering is important for runway photography that must be done with available light and the spotlighted model is set against a dark, sometimes black background. Camera was an Olympus E-1 with an Exposure of 1/250 sec at f/3.5 and ISO 400 in Shutter Priority mode to minimize any subject motion.
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Along with photographer Barry Staver, Joe is co-author of Better Available Light Digital Photography that’s out-of-print but new copies are available for $21.88 or used copies for giveaway prices—less than three bucks—from Amazon, as I write this. Kindle version, for some reason, is really expensive.