I spent two years blaming my lens for soft street photos. Turns out I was just bad at focusing.
Autofocus is great when your subject stands still and poses. Street photography doesn't work like that. People move, you move, the moment is gone before your AF motor finishes hunting.
Zone focusing fixed this for me. You set the aperture and focus distance once, and everything in a certain range is sharp. No focusing per shot. You just shoot.
What Is Zone Focus
Zone focusing means you manually set your lens to a specific distance and stop down enough that depth of field covers a range around that distance. Anything within that range is acceptably sharp.
You trade exact focus for speed. On the street, speed wins.
The Hyperfocal Cheat
Hyperfocal distance is the focus point where everything from half that distance to infinity is in focus. It's the maximum depth of field you can get at a given aperture and focal length.
Here's the practical version. I shoot 35mm. At f/8, hyperfocal distance is about 5 meters. That means everything from 2.5 meters to infinity is sharp. I just set focus to 5m, set f/8, and shoot.
Here are the numbers I use ( 35mm full-frame ):