fixed-focus lens

Camera lens whose focal distance is pre-determined at the time of manufacture and cannot be adjusted by the user. It is typically designed to deliver great depth of field, that is, reasonable sharpness for all depths of an image starting from the hyperfocal distance — the minimum distance required from the subject for it to be in focus. For this, they usually have a small aperture (opening for the incoming light to pass through). Such lenses are typically used for cheap and compact cameras, including box cameras and phone cameras.