In photography, the metering mode refers to the way in which a camera determines exposure. Cameras generally allow the user to select between spot, center-weighted average, or multi-zone metering modes. The different metering modes allow the user to select the most appropriate one for use in a variety of lighting conditions. In complex light situations professional photographers tend to switch to manual mode, rather than depending on a setting determined by the camera.
Honeycomb Metering on a Dynax 5D. The AF point was set to the eye of the toy; the camera has been able to produce a good exposure, by not being fooled by the strong back lighting of the out of focus areas.
In photography, exposure is the amount of light per unit area reaching a frame of photographic film or the surface of an electronic image sensor. It is determined by shutter speed, lens F-number, and scene luminance. Exposure is measured in units of lux-seconds, and can be computed from exposure value (EV) and scene luminance in a specified region.
White chair: Deliberate use of overexposure for aesthetic purposes
Two similar images, one taken in auto mode (underexposed), the other with manual settings
Buildings and trees photographed with an autoexposure time of 1/200 s
A street view of Taka-Töölö, Helsinki, Finland, during a very sunny winter day. The image has been deliberately overexposed by +1 EV to compensate for the bright sunlight and the exposure time calculated by the camera's program automatic metering is still 1/320 s.