Mamiya PRO 645 - Manual (Page 26)

Reading the Depth of Field Scale
Depth of field is defined as the zone
of sharpness before and behind the
plane of focus. It depends on cam-
era subject/distance, focal length of
lens, aperture setting and distance
the lens is focused at.
In addition to visual observation, the
Depth of Field can be determined by
using the Depth of Field Scale on
each lens. f/stop numbers appear
on both the right and left side of the
red index mark in the center of the
scale ring. Simply read the figures
which appear above the f/stop num-
bers on the distance scale of the
Iens.
For example, with the 80mm f/2.8N
lens focused at 3m and the aperture
set at f/22, the depth of field scale
indicates that the zone of sharp fo-
cus will extend from about 2m to 6m.
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