17
* When using finders with a built-in exposure meter, exposure meas-
urements should not be taken with the depth of field preview lever
depressed, as the shutter speed indicated will cause over-exposure.
This is because proper exposures are obtained with exposure meas-
urements made at the full aperture.
18. Setting the Aperture Ring (con’t)
19. Focusing Adjustments
The lens is focused on the subject, by rotating the focusing ring in
either direction, while checking the effect on the central matte sur-
face area of the focusing screen (standard type).
20. Distance Scale and Depth of Field Scale
A. To adjust the lens to the required distance, without use of the find-
er, simply rotate the focusing ring and set the distance opposite the
orange-colored index. When the lens is focused, there is an apparent
zone of sharpness, both in front and back of the focused plane, which
is known as the depth of field.
* See the depth of field table for the Zenzanon-PG 100mm (32. Depth
of Field Tables.)
B. The depth of field scale, next to the distance scales, shows the zone
of apparent sharpness at any lens opening or distance and is made
up of identical pairs of apertures on both sides of the distance index.
These identical pairs of apertures indicate the distance that will be in
focus at these apertures. For example, if the 100mm lens is focused at
a distance of 3 meters, it can be seen from the depth of field scale
that the zone will extend from 2.2 to 4.8 meters, when a lens opening
of F22 is used.
