Hyperfocal Distance & Zone Focusing

This entry is aimed at those who want critical focusing control in their work. The techniques apply to working with a fixed focal length lens and working in manual focus.

Image: To make sure that focus was sharp from the foreground of this old truck to the facing truck in the background I worked in manual focus mode with a 24mm lens and used the hyperfocal distance technique described in the text. Copyright: George Schaub

Focus on an object very far away and take a moment to look at the distance scale on the lens; you might see that the distance setting is beyond the last numerical value on the distance scale (usually that's 30 feet on a 50mm lens) and is marked with an infinity sign. Now check the parameters of the f/16 notation on the depth of field scale-this shows that your zone of focus stretches from about 15 feet (the distance on the border of the f/16 mark on the left side of the depth of field scale) to well beyond any marking on the distance scale. As there is no distance beyond this infinity, this setting tells you that you are in focus from 15 feet to, well, the moon and beyond.
But what about the fact that you have the right side of the f/16 depth of field hash mark well beyond any footage indicator-does this mean you are "wasting" depth of field potential? In a word, yes; but there's an easy way to get it back. (Note, in some lenses the footage markers within the depth of field scale work in reverse to how we're describing it here. If your camera works in this fashion, just reverse left and right as you read on, Actually, the direction in which the distances move is much less important than the idea of manipulating distance settings on your lens to maximize depth of field.)
If you're shooting from the rim of the Grand Canyon out into the distance, your depth of field setting is unimportant, as long as the infinity setting is enclosed within the hash marks of the aperture in use. But if you have subjects in the scene that sit closer than 15 feet, you can set the lens so that you still have focus at infinity and include a focused item in the foreground as well.
The technique you use to do this is called using hyperfocal distance. The first step here is to turn off autofocus. Then you align the infinity marker with the right-side hash mark on the depth of field scale with the aperture number in use, then take note at what distance the left side aperture number falls. The left side number is the minimum distance at which you will have focus, when your furthest point of focus is at infinity.
For example, if we set hyperfocal distance on a 50mm lens at f/16, we find that our zone of sharpness is about eight feet to infinity. This is a pickup of seven feet from our previous setting; we don't lose anything by setting hyperfocal distance, we just gain a bit more foreground sharpness.
You can also manipulate the zone of focus when the farthest shooting distance is less than infinity. Called zone focusing, it's based on the same idea as hyperfocal distance; you manipulate the depth of field scale so that aperture settings enclose certain distances-these distance settings become your zone of sharpness.
For example, let's say that our farthest subject is ten feet away; by setting the number 10 next to the f/16 hashmark on right side of the depth of field scale, we see that we know have a zone of sharpness from about 4&1/2 to 10 feet. Likewise, setting at the 30 foot mark shows a near-focus of seven feet. Keep in mind that these settings are estimates of the actual depth of field; however, the settings certainly will be close enough for most of your shooting needs.
Pre-setting zone of focus can be a real help when you're doing spontaneous candids, or when you just don't have time to focus each shot. By pre-setting your zone of focus so that you can shoot without worrying about focus from, say, four to fifteen feet, you can photograph without bringing the camera to your eye, and still get almost every shot you take in focus. Of course, your composition may be a bit off, but "shooting from the hip" is an old tradition with candid street photographers.
Of course, there are times when you can be more deliberate about what you want to bring into focus. By using the depth of field scale you can make fairly precise settings to get the most out of the available zone of sharpness. For example, let's say you're shooting a statue in front of a building and want to include both the statue and building in focus. Without using or being aware or depth of field manipulations you might not get the effect you wanted; with them you can play some amazing visual tricks. It's safe to say that depth of field manipulations are underused by most photographers, especially those with autofocusing cameras; get a handle on them so you don't lose out on their amazing potential to make the most out of every shot.
The depth of field preview button is an important player in this game as it stops the lens down to its taking aperture, thus allows you to see the effect the lens setting has on focus. At some apertures, such as f/16, the viewing screen becomes quite dark; so dark, in fact, that you may have trouble seeing what's going on. If this happens, open up another stop so you can see focus on the viewfinder better, then stop down to your selected aperture when you take the shot. This won't give you an exact idea of the depth of field at your taking aperture, but it will certainly give you a better idea of final picture focus than will looking through the lens at maximum aperture. If your camera does not have a preview button, get another camera and in the meantime use the depth of field scale on the lens.