Adjusting The Field Diaphragm (For The Diascopic Illumination) - Nikon ECLIPSE MA200 Instructions Manual

3.23.3

Adjusting the field diaphragm (for the diascopic illumination)

The field diaphragm is used to limit the irradiation area of the lamp to the view-field of the microscope.
View the supporting pillar for dia-Illuminator 100W from above, then turn the field diaphragm dial
counter-clockwise to open the field diaphragm, or turn the field diaphragm dial clockwise to stop down the
diaphragm. Normally, stop down the field diaphragm to a size that circumscribes (or inscribes) the view-field.
An unnecessarily large irradiation area will result in stray light and flare, thereby reducing the contrast of the
optical image. For photomicroscopy, the field diaphragm should be stopped down to a size slightly larger than
the area to be captured. Avoid stopping down the field diaphragm too close to the frame size to be captured,
as it may result in vignetting.
* Perform the field diaphragm adjustment after completing focusing and centering for the condenser lens.
Field
diaphragm
dial
Condenser
focus knob
Condenser
centering
screws
Field diaphragm image
View-field
Move the field diaphragm image into the center of
view-field. Adjust its size to match the view-field.
Figure 3.23-4 Adjusting the field diaphragm
Chapter 3 Operation Details
1 Place the 10X objective into the optical path.
2 Stop down the field diaphragm by turning the field
diaphragm dial on the supporting pillar for
dia-Illuminator until the field diaphragm image
comes into the view-field.
3 Turn the condenser focus knob of the supporting
pillar for dia-Illuminator to focus on the field
diaphragm image.
4 Move the field diaphragm image to the center of
Condenser
the view-field by turning the two condenser
focus knob
centering screws on the supporting pillar for
dia-Illuminator.
5 Place the 50X objective into the optical path.
6 Adjust the size of the field diaphragm image to
closely match the size of the view-field, by turning
the field diaphragm dial on the supporting pillar for
dia-Illuminator.
7 Move the field diaphragm image to the center of
the view-field by turning the two condenser
centering screws on the supporting pillar for
dia-Illuminator.
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