Understanding Hyperfocal Distance

Hyperfocal distance is determined by the aperture, focal length of a lens, and sensor type of the camera. As mentioned in my post on Depth of Field (DOF) yesterday, the DOF Calculator will provide the hyperfocal distance value. Here, I will attempt to give a simplified explanation on hyperfocal distance based on my understanding.

What is Hyperfocal Distance?

Hyperfocal Distance is the distance at which the focus using the given aperture and focal length, to produce the greatest Depth of Field (DOF) that stretches to infinity. The value of the hyperfocal distance means anything starting from the distance that is 1/2 that value to infinity will appear to be acceptably sharp in focus (or within an "acceptable blur" that will be sharp enough to our eyes).

The illustration above should be simple enough to understand. There are 3 basic principle to understand on hyperfocal distance:

• Hyperfocal Distance decreases with smaller aperture (i.e Big F-number).
• Hyperfocal Distance decreases with shorter focal lengths.
• Type of camera sensor affects DOF - putting aperture and focal length at constant, a full-frame camera will produce have a shorter hyperfocal distance as compared to cropped body camera.

Note: When looking at hyperfocal distance, greater depth of field can be reaped with a shorter hyperfocal distance because this means that the starting point where things get sharp (i.e 1/2 hyperfocal distance) is nearer to the photographer and the depth of field to infinity can be maximized.

How is Hyperfocal Distance Useful?

Want Everything Behind Subject to be Sharp

Assuming a full frame camera focusing on a subject 8m away at F8 using 50mm lens, the depth of field produced is about 29m. Anything beyond the Far Limit Distance of 33.8m will be blur.

However, if focusing at hyperfocal distance of 10.5m, everything to infinity will be sharp. Although the focus is behind the subject, the subject will also remain sharp in focus.

Want a Near Object to be in Focus When Taking Landscape

In photographing landscape, typically the focus will be on the landscape (e.g. mountain) which is far away (infinity) using a wide-angle lens (e.g. 24mm). However what if there is an object (e.g. a flower) that is 2m away from you that you want to capture sharply in your composition?

This is when hyperfocal distance is useful. By focusing at hyperfocal distance, the object that is 2m in front of you can stay acceptably sharp in the picture taken.

In What Situations can Hyperfocal Distance be Used?

I typically use hyperfocal distance in photographing landscape, so that I can reap the most benefit by having the farthest to the closest possible objects in the picture frame to be sharp in focus.

There are other interesting articles in the Internet illustrating how hyperfocal distance could also be used in weddings like group photos or on people crowd.