Depth-of-Field. In simple terms DOF can be defined as “the distance in front of and beyond the subject that appears to be in focus.” Seems simple, right? But the myriad factors that contribute to a composition’s Depth of Field are often misunderstood (and frequently overly-simplified), leaving many filmmakers and photographers with a false understanding of the physics at play. And it goes without saying that when you educate yourself on the factors that contribute to DOF, you gain a greater level of control over your images, whether you are a cinematographer or photographer, professional or novice. A grasp of the basics of DOF become even more essential when shooting with a 35mm lens adapter system for video cameras.
That is why I am pleased to present the following 20 minute primer on the subject of Depth of Field, filled with practical illustrations and explanations of the physics at work in a lens, and simple examples that will help elevate your understanding of the subject. It thoroughly covers the topics of aperture size, focal length, camera-to-subject distance, circle of confusion (CoC), hyperfocal distance, and infinity focus. I believe that you’ll find it a very informative and approachable explanation of a somewhat arcane and confusing topic.
This excellent video tutorial was created by Justin Snodgrass of snodart.com, and is shared with permission here at FreshDV. Justin is a young filmmaker with a passion for screenwriting and storytelling. He has earned accolades for his entries into regular DVXuser film festivals, and current projects include a short film for David Concannon in partnership with DP Tim Young. You can view more of Justin’s work at snodart.com
You can download a high-quality version at Justin’s site.
If you wish to learn more about focus as it pertains to 35mm adapters and production in general, check out our in-depth video series on The Art of Pulling Focus, taught by a seasoned First AC with 30 years of filmmaking experience.
This FreshDV Classic article is licensed and republished at ProVideoCoalition with permission.