The hyperfocal distance is the closest distance at which you can focus a lens so that the depth of field still reaches infinity. It depends on the focal length and the aperture.
When you focus at the hyperfocal distance, everything from about half that distance to infinity looks acceptably sharp. This gives the greatest possible depth of field for that aperture. Landscape and street photographers often use it. You can find it with a depth of field scale, a chart or an app.
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