Zone focusing

Zone focusing is a method of focusing by estimating the distance from the camera to the subject and setting the focus using a distance scale printed
on the camera lens. It is most commonly used in candid photography where there is no time to set the focus through the viewfinder, or when shooting from the hip.

Very compact cameras (especially half-frame) that focus manually (but that don’t have a precise method of adjusting focus in the viewfinder) may feature focus guides that are broken down into three or four distances, and labelled with icons for ease of use.

Portrait / Close (1m, 3ft)
Group / Medium (3m, 10ft)
Scenery / Distant (∞)