Depth Of Field; Depth-Of-Field Preview Lever - Nikon F2AS PHOTOMIC Instruction Manual

DEPTH OF FIELD

Depth of field refers to the zone of acceptable focus extend-
ing in front of, and behind, the plane of sharpest focus. Within
this zone, image blur is negligible and everything may be
considered as being in sharp focus. Three factors greatly in-
fluence the depth of field: the focal length of the lens in use,
the camera-to-subject distance, and the taking aperture. The
smaller the aperture and the shorter the focal length of the
lens, the greater the depth of field. Also, the closer the sub-
ject, the shallower the depth of field. These three factors can
operate independently or in conjunction with one another,
with any one factor capable of partially canceling the effects
of the other. Thus, by careful selection and use, the photog-
rapher can exercise wide creative control over the final pic-
ture.
Depth-of-Field Preview Button
As most Nikkor lenses are operated at full aperture for ease
of focusing, visualization of the depth of field at the shoot-
ing aperture may be difficult. Thus, the camera's depth-of-
field preview button often can come in handy. The depth-
offield preview button lets you check (or "preview") the zone
of sharpness at any time before (or after) shooting. Simply
by depressing the button, the lens is stopped down to the
preselected aperture to allow you to see how much back-
ground and foreground is in or out of focus.
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