Zone focusing is one of the most powerful tools street photographers have at their disposal. In this article I will explain what zone focusing is and how street photographers can use this technique to their advantage.
I first experimented with zone focusing when I had just started with street photography. I didn’t know what zone focusing was, but I had to use the technique out of necessity.
Back then, I used a Nikon D7100, a DSLR camera that proved to be horrible for street photography.
The auto-focus was very slow, but I could live with that. The real problem was that the camera wouldn’t focus when I was using the LCD screen instead of the viewfinder. It just would not! To deal with the problem, I used a technique that – as I later learned – is called zone focusing.
What is Zone Focusing?
Zone focusing is focusing the camera to a predetermined distance. That combined with a narrow aperture (f/8 or narrower, for example f/11 or even f/16) will give you a very wide depth of field, providing you with a wide range or ‘zone’ in which your subject will always be in focus. So focus once and as long as your subject is in the ‘zone’, it’ll always be in focus!
The Benefits of Zone Focusing
The benefits of zone focusing are huge. When your subject is in the zone, you won’t have to waste time focusing. No more adjusting your focus point, no more having to focus and recompose. Just click and never miss a shot!
Sweet! So How Does It Work?
OK, have a look at the figure below:
Figure 1: Zone focusing
As you can see in this figure, I have set my aperture to f/8. Given the sensor size of my camera and the focal length of my lens, I have calculated that if I pre-focus at a point 1.8 meters (approx. 5.9 feet) from my camera, everything from 1.05 to 6.25 meters (approx. 3.4 to 20.5 feet) will be in focus.
That’s not all! If I change my aperture to f/11 and leave the focus distance at 1.8 meters, the in-focus zone expands to infinity!
Figure 2: Going hyperfocal
As you can see in figure 2, if I set my focus distance to 1.8 meters with an aperture of f/11, everything between 0.9 meters and infinity will be in focus. That’s street photography heaven!
Wait… Math? Forget It!
Hold your horses! You don’t have to make a single calculation. There is an app for that. Better still, there are a lot of apps for that, both for the iPhone and Android. If you can tap some buttons on a smartphone, you will have no problems getting all the right settings.
After a while you will find that if you keep using the same camera and lens, you won’t need the app anymore. You can zone focus on intuition.
I won’t recommend a specific app to you, but if you search for ‘zone focusing’, ‘hyperfocal’, or ‘depth of field’ on the App Store or on Google Play, you will certainly find the right app for your needs. Some of the apps will even display an insightful diagram like the ones I showed above, to help you get started.
Great! So What Do I Need?
You will need a camera that will allow you to control the aperture and lets you focus manually.
Having a distance scale on the lens is very helpful too. It will let you set the focal distance easily. If your lens doesn’t have a distance scale and a distance scale isn’t provided in-camera, you can still use zone focusing. It will be harder though. You’ll have to find an object that’s approximately the desired distance from your camera for your autofocus to focus on. After having focused with your autofocus, switch to manual focus immediately and don’t touch the focus ring.
It’s best to use a prime lens, i.e. a lens that cannot zoom. I have used a zoom lens before while zone focusing and kept the focal length constant. It’s doable, but it’s not very convenient.
And oh yeah… You will need an app to get you started, or do the math yourself ?.
Are There Drawbacks to Zone Focusing?
Unfortunately there are. One of the biggest drawbacks is that a photo will get progressively less sharp when you set your aperture smaller and smaller. This is called ‘lens diffraction’. Lens diffraction will typically become a problem if you want to reach hyperfocal mode where you’ll often want to use a smaller aperture. Try to overcome this problem by adjusting the focus distance.
The smallest aperture I use is f/16, but 98% of the time I won’t go below f/11.
Another drawback is that using a small aperture means that less light is hitting the camera sensor. You’ll need to compensate that by upping your ISO and/or using a slower shutter speed. Just don’t be too afraid of high(er) ISO’s!
Sometimes you’ll need a narrow depth of field to get the effect you’re looking for. In that case, zone focusing is not the right tool.
Please note that the concept of focus in zone focusing is not an absolute rule. Subjects in the zone will be in focus to an acceptable degree. But what is acceptable to you, might not be acceptable to someone else. The more your subject is near the edges of the zone, the less sharp your subject will be.
Will you be trying out zone focusing, or are you already experienced? Please drop me a line in the comments! I would really like to hear from you!
Update: comments section removed