Nikon DIAPHOT 300 - Page 20

7. A djust the diaphragm.
Narrow the field aperture diaphragm
until it is slightly wider than the area to
be photomicrographed.
Adjust contrast, depth of focus and
resolution with the condenser aperture
diaphragm. (This diaphragm should
usually be set to a range of 70 to 80%
of the objective's numerical aperture.
See page 22 . )
Figure 3-7
8. C h e ck the exposure time.
Check the exposure time displayed on
the camera. Adjust the brightness so
that the exposure time is longer than
1 /8 of a second.
• Color film: Adjust with the ND filters.
(Keep the NCB1 1 filter in the optical
path.)
• Monochrome film: Adjust with the ND
filters or by varying the lamp voltage.
Figure 3-8
9. P r event external light from
coming in.
Fit the finder cap (option) to the camera
finder. (Keep the finder cap on the
finder except when the exposure time
should be checked through the finder.)
Set the turret assembly to C. (This
applies to the eyepiece tube BT1 ,
especially for long-time exposure.)
Figure 3-9
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