Chapter 3 Usage of Components
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3.13.3 Using the Field Diaphragm Slider
Inserting or removing the field diaphragm
The field diaphragm is a diaphragm for restricting the
illumination range. The entire field diaphragm can be
placed into or removed from the optical path by
inserting or removing the field diaphragm slider.
Therefore, if the field diaphragm has been adjusted
to match the specified optical path beforehand, the
field diaphragm status can be restored simply by
operating the slider.
Operation:
Field diaphragm slider
Field diaphragm
Push in
until it clicks into position.
The field diaphragm
enters the optical path.
Pull out
to the limit position.
The field diaphragm
is removed from the
optical path.
Moving the field diaphragm slider
Using the field diaphragm slider
If the field diaphragm has been adjusted to match the diameter of the camera beforehand, a large field of
view can be observed through the binocular part just by pulling out the slider. Inserting the slider back in
place enables the camera to be used straightaway.
Using the field diaphragm slider during large field-of-view microscopy
To perform microscopy with a large field of view with a field number of equivalent to or more than 22,
remove the field diaphragm slider from the optical path.
Adjusting the size of the field diaphragm
Adjust the size of the field diaphragm using the field
diaphragm open/close lever of the field diaphragm
slider.
Operation:
Field diaphragm
open/close lever
Field diaphragm
Push it upward.
The diameter of the
diaphragm increases.
Push it downward.
The diameter of the
diaphragm decreases.
Ordinarily stop down the diaphragm to the degree
that it circumscribes (or inscribes) the field. An
illumination range wider than necessary causes
stray light to come in from other sources. As a
result, a flare occurs and the contrast of the
optical image decreases, and the specimen might
have a wider range of discoloration.
Moving the field diaphragm slider
Size of the field diaphragm when capturing images
Adjustment of the field diaphragm is especially important for digital cameras. Generally good results are
obtained by narrowing the field diaphragm to a range a little broader than the capturing area (shooting
range) of the camera.
Field diaphragm
open/close lever
Centering screw
(top)
Centering screw
(bottom)
Field
diaphragm