In manual focus mode, one of the things you can do is set the lens to the hyperfocal distance, which will depend on the actual focal length of the lens and the f-stop you pick. At this setting, everything between infinity and the near limit of the depth of field pertaining to the hyperfocal distance will be in focus. This comes in very handy when you strive to attain the greatest possible depth of field at a given aperture setting.
