Luminaire Comparisons

Produced by: Light Modifiers Rental
Written by: DP:
Camrin Petramale & Gaffer: Neil Adamson

Part 3: Falloff

We are taught that light behaves a certain way, and that falloff is calculated by the Inverse-Square Law. While the Law is scientifically sound in theory, how we practically use and manipulate light on set changes falloff outcome. Understanding that Illumination drops as the distance from a light source increases, and Illumination increases as the light is moved closer, many of us were taught that there is a fixed rate of change that can be used to approximate this relationship between distance and illumination on set. The inverse-square law explains this falloff rate according to the following equation:

Inverse-Square Law

The easiest way to understand the Inverse-Square Law is usually to apply the rule that if you double the distance, you take ¼ of the original intensity. Similarly, if you triple the distance, you would take 1/9 of the original intensity. This is where the name of the law comes from (inverse - taking the reciprocal of the distance - 2 = ½  square - squaring that distance - ½2). However, while this law is absolutely true, the variables at play will often produce results that prove problematic when trying to use this formula on set.

Energy at new distance  = original energy / new distance2

Figure 1 - Standard depiction of the Inverse-square law at work..

Consider the following situation:

Light Modifiers Rental .png

Copyright © 2020

Light Modifiers Rental
Camrin Petramale & Neil Adamson

Rent with Us

Ready to book your rental or have questions on our services? Feel free to contact us at anytime.

Staff With Us

With producer mentality in mind, Light Modifiers Rental helps staff productions from music videos to large commercial projects and indie films. Being union friendly allows us to recommend great candidates from HMU to DPs for your production. 

Contact Us

2414 West Cullerton 
Chicago, IL 60608
Tel: 773-940-2654

  • White Instagram
  • White Facebook Icon
  • White LinkedIn Icon
  • White YouTube Icon
  • Google Play - White Circle

Light Modifiers Rental is a Subsidiary of Light Modifiers, your friendly neighborhood lighting guys