Photography 101: Advanced DOF Calculations

Stephen F. Dennstedt

This video challenges conventional wisdom when it comes to advanced depth of field (DOF) focus calculations. It’s a YouTube video produced by Thomas Heaton who is a young and accomplished British landscape photographer based in the United Kingdom. I’m typically old school traditional when it comes to photography, but I am open-minded enough (I think) to learn new and better ways of doing things.

When shooting near to far landscape scenes photographers strive for maximum DOF. In other words you want your foreground subject matter to be acceptably sharp while keeping the middle ground and background areas acceptably sharp as well. Using a wide-angle field of view (FOV) usually helps with this goal: 16mm, 24mm, 28mm and 35mm are all common focal lengths (FL). Also, a smaller aperture (larger f/stop) increases DOF: f/8 through f/16 are typically used.

Back, for a moment, to conventional wisdom: Conventional wisdom dictates you use the Hyperfocal Distance for maximum DOF throughout the scene. There are complicated algorithms to calculate this distance, and with today’s technology there are even SmartPhone apps that will quickly calculate this focal point for you. But as a general rule of thumb the Hyperfocal Distance in a scene is approximately 1/3 of the way into the scene, this theoretically ensures that there will be acceptable sharpness throughout the image. And this is the conventional wisdom I’ve always used (and depended upon) when shooting landscapes requiring maximum DOF.

1/100s @ f/16 ISO 100 @ 24mm

The above image was shot in the Atacama Desert of northern Chile this past year. It’s not the best example of what I’m talking about because it’s only a low resolution web-size image and the wind was blowing at about 40 knots per hour (blurring the tufts of grass in the foreground). However, it illustrates the goal: I wanted the tufts of grass and sand (in the foreground), as well as the lake and mountains (in the middle ground and background) to all be acceptably sharp. The camera settings included in the caption reflect that goal—my hyperfocal focus point was about 1/3 of the way into the scene. Now Thomas comes along and challenges that conventional wisdom. Damn it.

He makes the case that simply focusing at infinity  will accomplish the same thing. Heresy pure and simple. The empirical evidence suggests that the FL/FOV (wide-angle) and small aperture (f/8 through f/16) is more important than the focus point. And, by God, he makes one helluva a case (with examples). He also explores finding the Hyperfocal Distance by using the DOF preview button on your camera (which can be very problematic when stopping down your lens in low-light—which is often the best time to shoot). I will know better when I prove it to myself, and I will definitely be experimenting with this new information. Anyway, enjoy the video and checkout Thomas Heaton.

 

Advertisements

6 responses to “Photography 101: Advanced DOF Calculations

  1. Great video. He’ll get a really hard time from the purists, but I’m sure he can defend his corner. Obviously, what works for one setup (full frame, 24mm , Canon) cannot be guaranteed to work on my crop sensor with a 18/55 . The thing that surprised me the most was how short the hyperfocal distance was. Less than 6 feet! You can tell I don’t do landscapes.. Thanks for sharing. R.

Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s