Every lens focused at a distance renders a *range* of distances acceptably sharp — some space in front of the focus point and rather more behind it. That range is depth of field, and zone focusing is nothing more exotic than choosing your aperture and focus distance so the range covers where your pictures happen, then leaving it alone.

At f/8 focused at 2 metres, roughly everything from 1.5 to 3 metres is sharp. That is the width of a pavement encounter. Set it, and every subject who passes through that corridor is in focus before you raise the camera — no half-press, no hunting, no missed moment while the autofocus decides. The camera becomes a box that is simply *ready*.

Three things widen the zone: a smaller aperture (f/11 over f/5.6), a wider lens (28mm gives more depth than 35mm at the same settings), and focusing further away (the zone around 3 metres is far deeper than the zone around 1 metre). Trade between them depending on light.

Modern autofocus is quick, but it must still decide *what* to focus on, and the street gives it a dozen candidates per frame — the railing in front, the bus behind, the face passing at the edge. Zone focusing removes the decision entirely. Photographers shot this way for decades before autofocus existed because rangefinder lenses carried depth-of-field scales on the barrel, and it remains how many street photographers work today.

The deeper reason is cognitive. Focus is one of the few genuinely urgent variables in a street frame; exposure and focus both pre-set means the only live problems left are where to stand and when to press. You watch the scene instead of the viewfinder readouts, and anticipation — not reaction speed — is what gets the frame.

Rangefinder and many manual lenses make this trivial: turn the ring to 2 metres, read the f/8 marks on the scale, done. On autofocus-native cameras, switch the lens or body to manual focus, focus once on something at your chosen distance (a kerb, a doorway, your own outstretched-arm distance doubled), and stop touching it. Cameras with focus distance indicators or focus peaking make the check easy.

Then practise the distances. The skill that makes zone focusing sing is judging 1.5 metres and 3 metres by eye, instantly. Walk your zone: know what one big pavement slab is, what a parked car's length is. Within a session or two the estimation is automatic, and you will trust the zone enough to shoot without confirming — which was the entire point.