Understanding Metering

Metering is how your camer evaluates the light of a scene to determine the correct shutter speed, aperture, or ISO.

Back in old days of photography … cameras were not equipped with a light “meter”, which is a sensor that measures the amount and intensity of light. Photographers had to use hand-held light meters to determine the optimal exposure.

Today, every digital camera has an integrated light meter that automatically measures the reflected light and determines the optimal exposure. The most common metering modes in digital cameras today are:

1. Matrix Metering / Evaluative Metering - is the default metering mode on most digital cameras. It works by dividing the entire frame into multiple “zones” which are then all analyzed on a na individual basis for light and dark tones.

2. Center-weighted Metering - evaluates the light in the middle of the frame and its surroundings and ignores the corners. Compared to Matrix /Evaluative, Center-Weighted Metering does not look at the focus point you select and only evaluates the middle area of the image.

5. Spot Metering - only evaluates the light around your focus point and ignores everything else. It evaluates a singe zone / cell and calculates exposure base on that single area, nothing else. Spot metering works great for back-lit subjects.

4. Highlight-weighted Metering - many cameras have a highlight priority metering mode, which has an indicator icon similar to that of spot metering but with a star beside it. Highlight priority metering aggressively protects the highlight in your shots. This can be very useful if you have some brighter areas near you subject that you don’t want to overexpose.