Field Diaphragm - Nikon eclipse lv150 Instruction Manual

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Field Diaphragm

The field diaphragm open/close lever changes the size of the field
diaphragm. Adjust the size of the diaphragm until it circumscribes or
inscribes the viewfield.
About the field diaphragm
• The field diaphragm restricts illumination on the sample to the
area being observed.
• Illuminating an area larger than necessary can let in stray light,
creating flaring and reducing the contrast of the optical image.
• Proper operation of the field diaphragm is important during photomicrography. Generally, the
field diaphragm should be set to the area to be exposed on film, that is, to an area slightly
larger than the photographed area.
• Be sure to adjust the field diaphragm after centering it.
Centering the field diaphragm
1 Focus on the sample with the 10x objective by following the steps of bright-field microscopy
(p.16, 17).
2 Lower the field diaphragm open/close lever to reduce the field diaphragm opening.
3 Turn the two field diaphragm centering screws on both sides to move the center of the field
diaphragm image to the center of the viewfield.
If the illuminator LV-UEPI2 is used, insert a hexagonal wrench into the field diaphragm
centering holes on both sides and turn the internal adjustment screws.
4 Use the field diaphragm open/close lever and centering screws so that the field diaphragm
image is inscribed in the viewfield.
5 When starting observation, raise the field diaphragm open/close lever so that the field
diaphragm image is slightly larger the viewfield.
Image of field diaphragm
Eyepiece view field
III. Operation of Each Part
Image of field
diaphragm
Eyepiece view field
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