Subject distance Moving the camera closer to your subjects shrinks the zone of sharp focus. In extreme close-up or macro photography where the front of the lens is mere inches from the subject, the zone of sharp focus can be minimal. At these times, when depth can be measured in millimeters, smaller apertures will expand the zone and add the necessary depth of field to maintain sharpness. Conversely, focusing on a dis- tant object widens the depth of field with an expanded zone of sharpness. The degree to which