What exactly does "white plus black minus" mean in photography?

"White plus black minus" means to increase the exposure when shooting the overall bright (white) scene and decrease the exposure when shooting the overall dark (black) scene. (Usually this principle only applies when measuring light. Central focus metering and area metering don't need to do this, because these two metering modes have considered the light intensity of all scenes first. )

For example, when shooting a white snow scene, the camera will automatically think that it is overexposed, and it is necessary to artificially increase the exposure compensation, that is, white plus.

For another example, if you go into a coal mine to shoot, the camera will automatically think that the light is too dim. At this time, it is necessary to artificially reduce the exposure compensation, which is black reduction.

Extended data

White plus black minus is related to the metering mode of the camera. Camera photometry has a "18% gray principle", and exposure will be controlled based on 18% gray.

18% gray scale can show most of the scenes in our eyes, and the camera can get basically correct exposure results as the exposure basis in most cases. However, in some special cases, 18% gray source will lead to deviation of exposure results.

Exposure compensation is not only a technology, but also an art. The brightness of a work is actually an expression of feelings, and the tone of the work can be expressed through exposure compensation.

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