Restricting The Illumination To The Area Of The Specimen Being Viewed (Centering And Adjusting The Field Diaphragm) - Nikon Eclipse Ni-E Instruction Manual

Restricting the Illumination to the Area of the Specimen being Viewed
16.5
(Centering and Adjusting the Field Diaphragm)
The field diaphragm is used to restrict illumination to the area of
the sample being viewed.
Turning the field diaphragm lever of the epi-fluorescence
attachment changes the size of the field diaphragm. Pushing in
the lever opens the field diaphragm while pulling it out closes it.
For normal observations, stop down the diaphragm so that the
aperture boundaries circumscribe or inscribe the field of view.
Opening the field diaphragm too much and illuminating a broader
area than necessary will result in stray light entering the field of
view, generating flare and reducing the image contrast. In
addition, the specimen will become decolorized over a wider area.
Be sure to center the field diaphragm of the epi-fluorescence
attachment as follows before use.
■ Center the field diaphragm
(1) Pull out the field diaphragm lever on the
epi-fluorescence attachment to stop down the field
diaphragm.
(2) Turn the field diaphragm centering screw with the
provided hex driver (2 mm across flats) to move the field
diaphragm image to the center of the field of view.
(3) Push in the field diaphragm lever and open the field
diaphragm to match the size of the field of view.
(4) Turn the field diaphragm centering screw once again to
align the center of the field diaphragm image with the
center of the field of view.
Field diaphragm adjustment timing
Be sure to adjust the size of field diaphragm each time you change the objective. While it is not absolutely essential to
center the field diaphragm each time you change the objective, you should still perform a quick check and make
adjustments as necessary.
Chapter 3
Individual Operations
126
Diaphragm
P
F. S T O
opens
Field diaphragm
Field diaphragm
centering screws
Field diaphragm
image
Eyepiece
field ring
Adjusting the field diaphragm
A . S T O P
Diaphragm
closes
lever
Field diaphragm
image
Eyepiece
field ring