Lighting 101: Everything You Need to Know About Light Fall Off

Photographer Gavin Hoey recently produced a video for Adorama TV that tackles a critically important subject for photographers: light fall off. Mathematically captured by the so-called Inverse Square Law, it’s vital that photographers understand this property of light, especially when working with strobes.

Light fall off and the Inverse Square Law is a difficult and boring subject to try and explain in writing; you’ll quickly get bogged down in equations that will make most readers’ eyes glaze over. The best way to explain and understand this fundamental principle of light is to see it in action by creating a test scenario for yourself; the second best way is to watch someone else do it.

Enter Hoey.

In this video, Hoey sets up a photo shoot and demonstrates how changing the distance between his subject and his light source can completely change the character of the image. In the most basic terms:

• The closer your subject is to your light source, the faster the light hitting your subject will fall off from highlights to shadows, leading to high contrast, dramatic images.
• The farther your subject is from your light source, the more slowly the light hitting your subject will fall off from highlights to shadows, creating much more even lighting.

There are light meters involved and he does mention the formula at play, but the point of the video is to show, not tell, you how light fall off works. So if you’ve ever struggled to understand this property of light well enough to actually put it to use when capturing photographs, check out the full video up top.

This definitely isn’t the first (or second or third) time we’ve talked about the Inverse Square Law of light. But it’s a subject that’s definitely worth revisiting from time to time, no matter your skill level, and this is one of the clearest real-world demos that we’ve seen.