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复数形式
reciprocities
1
互惠
a condition in which two people, groups, or countries give each other mutual help or advantage
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互易性
the connection between the intensity of light and the time during which light is exposed to something in photography
Reciprocity in photography refers to the principle that the exposure of a photograph is determined by the relationship between the aperture, shutter speed, and light sensitivity of the film or sensor. Essentially, if one changes one of these settings, adjustments to the others can maintain the same overall exposure. Reciprocity is key for achieving correct exposure and balancing the light in a photograph.