Inverse Square Law: How Light Changes with Distance

Introduction: Light is essential in photography and other art forms. To capture great images, it's important to understand how light behaves. One principle that affects light is the inverse square law. In this article, we'll explain what it means and how it affects the way light falls on subjects at different distances.

Understanding the Inverse Square Law:

The inverse square law says that light gets weaker as you move away from its source. In fact, the light weakens in proportion to the square of the distance. So, if you double the distance, the light becomes only one-fourth as strong (1/2^2). And if you triple the distance, the light becomes only one-ninth as strong (1/3^2).

What This Means for Lighting:

Let's imagine a photographer with a subject standing five feet away from a light source. The light spreads out in all directions, creating a sphere of light. At five feet, the subject receives a certain amount of light.

Now, if the subject moves to ten feet away, the distance has doubled. According to the inverse square law, the light reaching the subject will decrease to one-fourth of its original strength. This decrease can significantly change how the subject appears and how well it's lit.

Applying it to Photography and Cinematography:

Understanding the inverse square law helps photographers and cinematographers control and manipulate lighting effectively.

For example, if a photographer wants to highlight a specific detail or create drama, they can move the light source closer to the subject. This increases the light intensity, making the subject more pronounced. On the other hand, if they want a softer, more diffused look, they can move the light source farther away.

Conclusion:

The inverse square law explains how light changes as you move away from its source. Knowing this law helps photographers and cinematographers achieve the desired lighting effects in their work. It allows them to control the mood, highlight important elements, and create captivating images and videos by using light effectively.

Inverse Square Law diagram posted-above will help you to understand light fall better. Please follow it if planning to shoot.

Keep Experimenting! Have wonderful and happy photography life.

Photographer & Blogger Prasenjeet Gautam (www.prasenjeetgautam.com) has above - posted the diagram.