Basic Features of Lenses

Depth of field refers to the area of the image that is clearly in focus. This varies depending on various conditions such as the focal length of the lens, aperture value (F value), focusing position, shooting distance, and the distance between the main subject of the photo and the background.

If the aperture value is changed, and all other conditions are kept the same, the larger the aperture setting (which correlates to a smaller F number), the shallower the depth of field becomes. The closer a photographer is to the subject, the shallower the depth of field will become; and the further away the subject is from the photographer, the deeper the depth of field.