InCamera Metering Systems p
Many modern cameras calculate exposure by taking ^ in not only the brightness but also color and contrast r values and subject distance.Your camera manual will provide details on the systems and how to ^
make full use of them.You might see these systems o referred to as matrix, multi-zone evaluative, partial, center-weighted, or spot. Most cameras g will allow you to select things such as aperture h priority (you nominate the aperture, the camera i selects the shutter speed); shutter priority (you g
A spotlighted athlete against a dark background presents a tricky lighting situation, but Ben Chen overcame the problem by setting his meter on partial, or center-weighted, mode. Jennifer Andersen executes a graceful ring jump at a performing arts event. Canon 1D, 70-200mm f2.8 lens, ISO 640, 1/250 at f2.8. © Ben Chen
A spotlighted athlete against a dark background presents a tricky lighting situation, but Ben Chen overcame the problem by setting his meter on partial, or center-weighted, mode. Jennifer Andersen executes a graceful ring jump at a performing arts event. Canon 1D, 70-200mm f2.8 lens, ISO 640, 1/250 at f2.8. © Ben Chen designate the shutter speed, the camera selects the aperture); program (the camera selects both aperture and shutter speed), or manual (you determine £ both shutter speed and aperture). The following p- are examples of three metering modes: ^ Matrix metering: This uses a multi-segment o matrix sensor (about 7 to 10 segments or zones, ° sometimes more) that detects scene brightness and o contrast in the whole scene to determine exposure. E When lenses that are compatible with the camera's
Ph auto focus and metering system are used (in Nikon, xSi i— these are D or G lenses; other manufacturers ^ have their equivalent lenses), subject distance is also factored in to give an even more accurate exposure. This is known as 3D matrix metering. As a general rule, matrix metering or its equivalent is very accurate and can be relied upon.
Center-weighted metering: As the name implies, this places emphasis on brightness within the center of the viewfinder. The camera will measure light over the entire scene but gives greater weight to a circle about 12mm in diameter in the center. You can compose your picture by placing the center circle on a specific area to determine exposure for that area. About 70-75 percent of the meter's sensitivity is concentrated on that 12mm circle.
Spot metering: Nearly all the meter's sensitivity will be concentrated on a small circle (in the 3-5mm range), either in the center of the
- Backlighting emphasizes the shapes of billowing spinnakers during the annual Oak Harbor race week in Washington State. Nikon FE2, Fujichrome 100, 300mm f2.8 lens, 1/500 at f8. © Peter Skinner
viewfinder or in some cameras in other selected areas of the scene. Spot metering is very handy when measuring light reflecting from a small, important part of the picture. It is useful in backlit situations when you want to determine exposure on a specific part of the main subject. Once mastered, spot metering is a powerful and creative tool.
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