Adjustment Of Aperture Diaphragm - Nikon ECLIPSE Si Instructions Manual

3.8

Adjustment of Aperture Diaphragm

The size of the condenser aperture diaphragm must be
adjusted according to the NA value of the objective in the
optical path.
The condenser is labeled with an adjustment position mark
for the aperture diaphragm, which serves as a guideline for
the adjustment position. Turn the aperture diaphragm lever
to the same number as the NA value of the objective in the
optical path.
Each time you change the objective magnifications, align
the aperture diaphragm lever to the same figure as the
magnifying power of the objective.
Aperture Diaphragm
 The aperture size is increased or decreased by turning
the condenser aperture diaphragm lever.
If the aperture diaphragm is closed, the brightness and
resolution are decreased but the contrast and range of
focus are increased. If the aperture diaphragm is
opened, the brightness and resolution are increased but
the contrast and range of focus are decreased.
Since the image resolution will be degraded when the
aperture diaphragm is closed too much, do not close the
aperture diaphragm too much except when observing a
specimen with extremely low contrast, such as a
near-transparent specimen.
 The aperture diaphragm controls the numerical aperture
of the illumination. Do not use it to control brightness.
Use the brightness control knob to control the
brightness.
Chapter 3 Detailed Explanation
Adjustment position mark for the aperture diaphragm
E PLAN
40x/0.65
∞
WD 0.65
90
Mark
→ Objective type
→ Magnification 40 times/Numerical aperture
0.65
/0.17 → Mechanical tube length
thickness 0.17 mm
→ Working distance (Distance between the tip
of the objective and the specimen) 0.65 mm
Specifications of objective
Aperture diaphragm
lever
∞
/Coverglass