A Simple Explanation of How Crop Factor Works

If you’re just starting out in photography, you may be confused with the term “crop factor” that’s thrown around when talking about cameras and lenses. Here’s a 10-minute video in which Mark Ryan Sallee of Michromatic explains the concept in an easy-to-understand way.

“Warning: Crop factor is math!,” says Sallee. “I explain crop factor, why people use it, and how to apply crop factor to various camera lenses and systems.”

We see how crop factor lenses only “see” a smaller portion of the image circle created by the lens in the camera compared to larger formats and sensors:

Sallee also explains how sensor size differences can allow different focal lengths to have the same angle of view (and why lenses are often described in their “35mm equivalent” focal lengths):

“Understanding crop factor won’t improve your photography, but it might keep you from saying something embarrassing on Reddit,” says Sallee.