Lighting 101: Inverse Square Law | Bergen County Photographer
By definition, the inverse square law dictates that the intensity of the light is inversely proportional to the square of the distance. But what does all that math have to do with photography? Good lighting is essential for a good photograph, so by understanding the inverse square law and how to apply it to photography will certainly help you become a better photographer.
Simply speaking, there is a very dramatic drop-off in light over distance. Meaning the closer you move the light, the brighter the light will be in relation to your subject. To use an analogy I heard a few years ago from photographer Lindsay Adler, imagine you have a bucket full of water. If you simply throw the water in front of you, the people who are closer to you are going to get very wet. The farther people are from you, the less wet they are going to be.
The inverse square law helps us understand why the light gets dimmer as as it gets farther from the source.
In Practice:
As your subject gets farther from the light source, light spreads out becoming dimmer or less intense, As you work with your light source , move it closer or farther away from your subject to vary strength and fall off. The background will also change color, getting darker the farther it gets from the light. If you are lighting a group of people move them closer together so they are more similarly lit.
This is just an introduction to the concept of light fall off. If you have any questions or any tip about this subject, comment below.
Darker background, light source, farther from subject
Lighter Background, light closer to subject