Understanding Depth of Field: Circles of Confusion and What Really Matters
Published: Thu, 02/19/26
Ever get caught up in the science of photography and wonder if we need to know it all to make strong pictures?
During an Introduction to Photography class or private lesson, someone usually asks about the science behind depth of field. Circles of confusion come up—a technical term for how our lenses render points of light. In simple terms, circles of confusion explain why parts of an image look sharp while others blur, depending on the lens opening. A smaller opening keeps more of the image sharp, while a wider one lets sharpness fall off faster.
But we don’t need to memorize the science to be excellent photographers. What matters is understanding how our choices—like changing the aperture—affect what’s sharp and what’s not. That’s the cause and effect that helps us compose thoughtfully and make pictures that say what we want.
Got questions about depth of field, focus, or anything else? Email me at sam@samdamico.com. I’m always happy to help us get clearer about photography, one question at a time.
