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In photography, the metering mode refers to the way in which a camera determines the correct exposure.
Examples of Metering Modes Cameras generally allow the user to select between spot, center-weighted average, or matrix metering modes. Spot Metering
Center-weighted average metering In this system, the meter concentrates between 60 and 80 percent of the sensitivity towards the central part of the viewfinder. The balance is then "feathered" out towards the edges. One advantage of this method is that it is less influenced by small areas that vary greatly in brightness at the edges of the viewfinder; as many subjects are in the central part of the frame, consistent results can be obtained. Average Metering In this metering mode the camera will use the light information coming from the entire scene and and averages for the final exposure setting, giving no weighting to any particular portion of the metered area. Partial area metering Some cameras support metering of just the central area of the frame. This mode meters a wider area than spot metering, and is generally used when very bright or very dark areas on the edges of the frame would otherwise influence the metering unduly. Matrix metering This mode is also called multi or evaluative; and honeycomb metering on some cameras. This metering mode was first introduced by the Nikon FA, where it was called Automatic Multi-Pattern metering. Here the camera measures the light intensity in several points in the scene (more expensive cameras generally measure in more points) and then combine the results to find the settings for the best exposure. How they are combined varies from camera to camera. Many cameras use focus distance from the lens (if that is available) or data from the autofocus system to help with this decision. More advanced cameras with many autofocus points will know what parts of the matrix of metering zones are in focus and thus likely to be part of the main subject. Such metering is sometimes called 3D Matrix Metering. The actual number of zones used varies wildly, from several..to over a thousand. However performance should not be concluded on the number of zones alone, or the layout. On a number of cameras this the default/standard metering setting. However, some photographers, including some advanced photographers and some older photographers who are accustomed to more traditional metering methods, may be uncomfortable with matrix metering, this tends to stem from a lack of clarity about "how" the camera reacts in certain situations. Many manufacturers closely guard the exact calculations used to determine the exposure. In general a number of factors are taken into consideration, these include: Autofocus point, distance to subject, areas in focus or out of focus, colours and hues of the scene, and back lighting. Matrix tends to bias its exposure towards the autofocus point being used, thus ensuring that the point of interest has been exposed properly. A database of many thousands of exposures is often pre-stored in the camera, and the processor can use a selective pattern to determine what is being photographed. Some users have problems with wide angle shots in high contrast, due to the large area which can vary greatly in brightness, it is important to understand that even in this situation, the focus point can be critical to the overall exposure. | ||||||||||
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