Making street photography with a manual focus camera can present several challenges our autofocus-wielding friends won’t face.
Let’s continue the journey into shooting street photography on film by concentrating on the absence of automatic focus. How can we guarantee acceptable, sharp images without missing those spontaneous moments of expression or emotion in the time it takes to manually dial in focus.
The answer? Setting a focal point and depth of field combination large enough that when your subject moves into that range, you are ready to take the shot. This is called zone focusing.
Zone Focusing, the Point of Focus, and Depth of Field
To fully grasp the concept of zone focusing, it is crucial to understand some fundamentals. While much of a photograph may seem “in focus,” only one point, one plane, of the scene, is in true focus. Everything stretching before or beyond this plane is gradually less focused.
In simple terms, this area ahead and behind the point of focus in which the image remains in “acceptable focus” is the depth of field.
Depth of field is most often adjusted by the choice of aperture. The physics behind this are both delightful and out of scope of this article, so I’ll keep it concise. A wide aperture (f/2.8, f/4, etc) results in a more shallow depth of field. With less depth of field, a lack of precision in focusing increases the probability the subject could fall outside the pocket of acceptable focus.
The opposite is, of course, also true. A narrow aperture (f/16, f/22, etc) extends the depth of field. Given the same lack of precision in focus, our subject may still be found acceptably sharp.
It is in the dynamic, unpredictable environment of the street that a photographer can use this knowledge of depth of field to their advantage by choosing an aperture and focal point combination, and in turn set a zone of acceptable focus.
In moments without time for higher precision, the street photographer need only compose and trip the shutter, safe in the knowledge focus is covered.
From the front working backwards, there is the aperture ring set to f/16. Beneath there is the focus ring on which is written the focal distance in feet (above) and in meters (below).
Nearest to the body of the camera can be found the depth of field scale. From the center of this scale stretching out to either end, note the pairs of f-stop numbers. 2, 4, 5.6 (marked but not written), 8, 11, and 16.
It is using this scale that depth of field can be estimated, and a zone can be selected.
Note: Each lens will have its own depth of field scale based on the focal length of the lens, the aperture area, and other optical considerations. For practice, it is advisable to stick to one camera and one lens, mastering the technique before moving on.
How to Use the Depth of Field Scale for Zone Focusing
Step 1: Set the f-stop to a narrow aperture, say f/16, maximizing the available depth of field.
Step 2: Choose a focal distance, in this case 3 meters, and set it on the center arrow on the depth of field scale. The focal plane is now, of course, 3 meters away.
The two 16 markers on the depth of field scale match a distance range on the focal distance scale.
It is clear that on the depth of field scale for an aperture of f/16, our depth of field stretches from just under 2 meters from the camera to 10 meters in the distance. Anything falling within that zone should be rendered in acceptable focus on the photograph.
Note: Acceptable focus is perceptual. Focus will experience a gradual drop-off the closer an object is to either end of the field, even if considered ‘acceptable.’
Choosing a Near or Far Point
Another option is to choose a near or far point on the depth of field scale instead of using the center marker.
Continue with the f-stop set to f/16 (step 1) maximizing the available depth of field.
Rather than choosing a focal plane, this time set a far field distance at the right-hand f/16 point on the depth of field scale.
In this example, the choice is of the preferred farthest reach of depth of field, 5 meters (step 2). Line of the 5m mark on the focus ring with the farthest right 16 on the depth of field scale. The corresponding point of actual focus is approximately 2.5 meters (matches the center marker on the depth of field scale), and the nearest point of the zone is 1.5 meters.
The other possible option would be to set the preferred closest distance of the field.
Depth of Field with a Wider Aperture
As a wide aperture reduces the depth of field, it is not recommended for zone focusing in street photography, giving – as it does – a larger margin of error. Nevertheless, other apertures may still be used.
Set the f-stop to f/8 (step 1), as one may do on a cloudy day, or in the middle of winter.
Choose a near focal distance on the depth of field scale, this time setting it on the left-most f/8 point (step 2). In this example, the closest distance chosen is 2m, so the furthest is approximately 3.5m – a clear contraction of the field.
When there is opportunity to dial in the correct focus, one should do so. For those instinctive blink-and-you’ll-miss-it moments when time is of the essence, use the zone focusing technique to pre-focus the lens to a comfortable zone and have the best chance of making the shot without vital seconds lost to manual focus.
My own practice is to dial in a zone-focused ‘back-up’ position as I walk around, focus as and when I need to, then return to the back-up, ready for anything unexpected that may appear.
Throughout the day, with changes of light, I may move between an aperture of f/16 and f/8 – adjusting my zone as I do so.
Let’s say I walk out my door to a bright sunny morning. I will start at f/16. I often get close to my subjects, so my near focus will be set to 1.5m or 2m. Subsequently, my focus point will be around 2.5m and the far point of my depth of field will be 5m.
If the clouds come out, I may have to stop down to f/8. With the knowledge that my depth of field has contracted, and the margin of error has increased, a small adjustment of zone is needed. My near point is set to 2m and my far point approximately to 4m.
Alternatively, on days where I feel shy or reluctant, I may prioritize my distant depth of field point first, knowing that I’m more likely to shoot things further from me.
Whether you’re shooting street photography in a crowd or on a quiet street, zone focusing is not only useful for catching short unexpected moments, but for times when the seconds of precise focus may alert the subject to the camera’s presence and the shot is lost.
In these moments, zone focusing is a blessing that momentarily transforms a manual focus Leica into a Smena 8m.
Becoming comfortable with zone focusing as a pre-focused, point-and-shoot last resort takes time and practice, particularly learning to judge the distances in front of the camera accurately.
Soft, blurred images may be the result of early adventures, however, persevere and soon it will become second nature.
When beginning, it can be useful to pick out repeating elements of the street to use as a rough guide to distance. Lamp posts, paving stones, fencing, the width of the pavement itself.
One of my friends (read: me) went so far as to carry a tape measure to the riverside boulevard, measuring bollard to bollard for reference. Whatever works.
A Quick Note on Hyperfocal Distance
So what exactly is that infinity symbol that may be seen on the focus ring. This can be used to set hyperfocal distance, which – in itself – is similar to zone focusing with one unique and useful difference.
Positioning the infinity symbol (step 2) on the far point for the chosen aperture (step 1) on the depth of field scale will set everything in the image, from the corresponding near distance on the scale stretching out as far as the eye can see, in acceptable focus.
Don’t, however, set the true focus point to infinity, as this will lose depth of field near to the camera. Stick to infinity as the far point for the aperture.
In my experience hyperfocal distance is more useful in Ansel Adams-esque landscape photography than in dynamic, fast-paced street photography, however, it may certainly have its use.
Hypothetically, one may wish the Eiffel Tower as sharp as can be from a few miles away, while also maintaining focus on the Parisian, casually smoking a Gauloise, in the café a few meters away.
My early experiments with pre-focusing and zone focusing were hit and miss, and I understand, particularly when shooting on film, it can be easy to feel discouraged with soft or wrongly focused photographs after development.
I used those that didn’t work to understand where I was going wrong. At which distances was I most likely to take a photograph? Was I pre-focusing too close or too far? When should I make a change to the zone?
Even now, I use zone focusing as a fallback position, but it has helped me get many a shot I may have otherwise missed, and as a street photographer, that is vital.