Nikon Epiphot 300 Manual page 65

(5) Photomicrographic Magnification and Frame Composition
Decide the objective and zoom magnification
and roughly focus on the sample. Adjust the
position of the sample or the stage to locate the
sample image within one of the photomasks
which corresponds to the loaded film.
• Magnification on the 35 mm film plane
Objective's magnification x zoom
magnification x2.5
• Magnification on the large format film plane
Objective's magnification x zoom magnification xlO
(6) Focusing
Perform focusing through the eyepiece with a built-in
mask.
G) Check the diopter adjustment of this eyepiece.
(See page 15 on diopter adjustment.)
CD Rotate the coarse focus and fine focus knobs of
the microscope to focus on the sample.
According to the magnification of the objectives,
focus on the sample as described below.
• High magnification objectives (50x or higher)
Bring the double crosshairs into focus. With the crosshairs in focus, slowly rotate the
fine focus knob of the microscope to focus on the sample image. Keep rotating the
focus knob until both the sample image and crosshairs come into focus together.
• Intermediate magnification objective (lOx or 20x)
Focus on the double crosshairs and the sample image in the same manner as in the
case of a high magnification objective. Then, turn your face slightly to right and left
to see the relative positions of the crosshairs and the specimen image from different
angles. Rotate the fine focus knob until their relative position becomes stable
(utilization of parallax).
• Low magnification objectives (5x or below)
Mount a focusing magnifier to the eyepiece with a
built-in mask. View the cross-hairs through the
focusing magnifier. While so doing, move the
magnifier back or forth to bring the crosshairs into
focus. With the crosshairs in focus, rotate the fine
focus knob until both the sample image and
crosshairs come into focus together.
59
Eyepiece photomask
8 cm x 11 cm
4" x 5"
'---- - ---,,�-center of 8 cm -
x 11 cm format
Diagonal double crosshairs
built in the eyepiece
Focusing magnifier
Eyepiece with
a built-in mask