- The inverse square law is a law of physics that explains a light source’s intensity in relation to the distance from a subject. In simple terms, it’s the explanation of the reason why light is brighter when it is closer to a subject and why that brightness diminishes as your move the light further from the subject. It provides mathematical information to help a photographer determine the amount of light that will be lost or gained by moving a light a particular distance.
Inverse Square Law
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