Nexcope NIB620 - Setting the Aperture Diaphragm (Condenser Diaphragm)

61
4.4.3. Setting the aperture diaphragm
(condenser diaphragm)
The aperture diaphragm (condenser diaphragm) adjusts the numerical aperture of
the illumination system. The correct setting of the aperture diaphragm is important
for the resolution, brightness, contrast and depth of field of the microscope image.
3
2
1
4
5
70-80%
100%
CT
Illustration 054: NIB630 - Adjusting the aperture diaphragm.
Before you start, check that:
• Changing lever for visual observation/photo is set to binocular part
• Universal phase contrast slider is set to bright field
• Transmitted light path is open
• No additional filters are swivelled into the beam path
• Object to be examined is placed on the stage
Aperture diaphragm lever (1) to the right:
The aperture diaphragm is closed  reduc-
ing resolution and brightness, and increas-
ing contrast and depth of field.
Aperture diaphragm lever (1) to the left:
The aperture diaphragm is open, which
increases resolution and brightness and
reduces contrast and depth of field.
The resolution, brightness, contrast
and depth of field properties are inter-
related and cannot be set independently.
Based on the specimen, adjust the ap-
erture diaphragm accordingly.
The aperture diaphragm must never
be used to adjust the light intensity,
only to regulate the contrast.
Adjusting the aperture diaphragm
Place the 10x objective into the optical path
and focus on the sample.
Close the aperture diaphragm  aperture
diaphragm lever (1) to the right.
Loosen the small screw on the eyepiece
sleeve to remove one of the eyepieces (2).
Use a suitable hexagonal screwdriver.
Insert the centering telescope (CT) (3) in the
eyepiece sleeve. Rotate the CT to adjust the fo-
cus. This reveals the objective pupil plane (4)
and the image of the aperture diaphragm (5).
In addition, a black phase ring of
the 10x phase objective is visible. This
does not interfere with the setting.
NIB630
4
A