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Camera ads, instruction books, tutorials, and photographers in conversation will sometimes mention metering patterns when discussing how cameras figure exposures. Evaluative metering, spot metering, center-weighted metering, and averaging are some of the terms used.
What is center-weighted metering and how does it affect how we use our cameras? Also, how do we know when to use center-weighted metering and how to use center-weighted metering?
What is Center-Weighted Metering?
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What is center-weighted metering? First part of the answer is that it’s not a metering mode, it’s a metering pattern. What does that mean? A metering mode covers how the camera sets the exposure controls, examples are aperture priority, shutter priority, and full program.
Before the camera exposure modes can adjust the settings, they need light value information from the metering cells that the computer brain can use to make the settings. In full manual mode, you still can use your meter, but now you're the one making the setting decisions.
A metering cell can read an average value of the entire scene, or it can be adjusted by the manufacturer to read in other ways. One popular pattern is called spot metering, which reads only a small portion of the scene, sometimes as small as 1 degree.
Evaluative metering compares meter readings from separate, distinct parts of the scene and makes exposure decisions based on a set of pre-programmed criteria. Center-weighted reads the entire scene but gives more importance to the central area of the scene.
18 Percent Gray
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Why any of this matters in the first place is because of how exposure meters are calibrated to read light. 18 percent gray, also called middle gray, has nothing to do with color vs black and white, it’s a term used to describe the average light value of most scenes.
Very early on in modern photography, camera makers knew that a lot of photographic images focus on what’s in the center of the viewfinder. It’s a lot more complicated than that but it shows a major reason why adjusting the metering pattern away from averaging the entire scene was more useful to photography in general.
Center-weighted metering on Nikon cameras use a ratio of 60/40 on enthusiast-level cameras and 80/20 on some professional cameras while center-weighted metering on Canon cameras is often 60/40 with partial area or spot metering also available in many cameras of either brand. You could expect the same from other major brands as well.
Real-World Examples
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Some real-world center-weighted metering examples of when to use center-weighted metering are portrait subjects that are slightly backlit and taking photos of popular places such as when on vacation.
While many photographers would likely try out their spot metering feature for more precise exposure control, the 60/40 metering pattern will work well for giving correct exposure reading in many situations. How to use center-weighted metering is as simple as centering the subject in the viewfinder.
It’s definitely not the perfect metering pattern for all subjects, which is why we have partial area and spot metering as well as multipattern, evaluative, matrix, or smart metering in many modern cameras.
In the minds and workflow of some photographers, the question of what is center-weighted metering is that it’s a very good way to have a compromise between spot metering and full area averaging.
Many photographers cut their teeth on this metering pattern and it still affects how we see scenes in our mind’s eye. Personally, I find myself compensating almost without consciously thinking about based on the cameras I learned on.
Find your own camera’s center-weighted metering pattern setting in your camera menu and try it out in different situations. It’s a good, general use metering pattern that can be
used in all of the exposure modes.