The Truth About Depth of Field (I Got This Wrong for 20 Years)

For years, I believed focal length had a major impact on depth of field in portraits—and I made creative decisions based on that. After testing it properly, I realized I was wrong. In this video, I walk through a full studio test from 35mm to 200mm and break down what actually controls depth of field: aperture, subject distance, focal length, and sensor size—and how they really interact. If you’ve ever struggled to predict background blur or felt like your settings weren’t giving you the results you expected, this will give you a clearer mental model of how depth of field actually works. ✅ Get equipment insurance & exclusive photography resources with PPA and receive $25 off your full membership: https://www.ppa.com/join/john-gress ✅ Learn about my workshops: https://johngress.com/workshops/ We’ll cover: What depth of field really means in practice The four factors that define DOF (aperture, focal length, subject distance, sensor size) Why aperture is your biggest creative lever My full mannequin test from 35mm to 200mm The truth about focal length and DOF in portrait photography How distance changes everything The 1/3–2/3 rule (and when it doesn’t apply) Hyperfocal distance explained Why diffraction can ruin sharpness at small apertures Whether you’re shooting portraits in the studio, working outdoors with shallow depth of field, or just trying to figure out why your photos don’t look the way you expect — this video will help you master DOF once and for all. 👉 Want to take your learning further? Check out The Photographer’s Journey — my complete framework for mastering photography and building your creative career: https://johngress.com/downloads/ Gear: Canon R5 Mark II Amazon: https://amzn.to/4cJZyir B&H: https://bhpho.to/3Yc4YyB Canon RF 28-70mm f/2.0 Amazon https://amzn.to/3vkEWbE B&H https://bhpho.to/426bKEM Canon RF 85mm F1.2 L USM Amazon https://amzn.to/3tHbPxm B&H https://bhpho.to/3L6f1Na 📌 Chapters 00:00 - Introduction 00:22 - How I got things wrong 02:26 - Defining DOF 03:05 - What goes in to Depth of Field 03:24 - Aperture 06:23 - Focal length 07:14 - DOF Test Results 08:43 - Distance to the subject 09:54 - 1/3 - 2/3 rule 10:48 - Hyperfocal Distance 11:42 - Diffraction 12:55 - Final Thoughts 📌 Hashtags #DepthOfField #PhotographyTips #PortraitPhotography #Aperture #LearnPhotography Click here for a full list of all the gear I use in the studio - https://johngress.com/gear/ Disclosure: This description contains affiliate links. If you use them, I may earn a commission — at no additional cost to you.