Centering The Aperture Diaphragm; Effects Of The Field Diaphragm; Aperture Diaphragm - Optika Italy IM-3 Serie Manuel D'utilisation

• Use without eyeglasses
Raise eye shields and observe at the microscope
placing eyes to the shields, avoiding external light to
disturb the observation. (Fig. 28)
9.8

Centering the aperture diaphragm

1. Place the specimen on the stage, insert 10x
objective into the light path and focus.
2. Pull the field diaphragm lever ① to fully close the
field diaphragm. (Fig. 28)
3. Rotate the two centering screws ② to bring the
bright spot in the center of the field of view.(Fig.
28)
4. Gradually open the diaphragm by inserting the
lever ①. The diaphragm is centered when the
diaphragm image is symmetrical to the field of
view.(Fig. 29)
5. In normal use, open the diaphragm until it
circoscribes the field of view.
9.9 Effects of the field diaphragm
Field diaphragm adjusts the illuminated area to obtain
a high contrast image.
Set the diaphragm according to the objective in
use until it circoscribes the field of view, in order to
eliminate unnecessary light to eyepieces.

9.10 Aperture diaphragm

• The Numerical Aperture (N.A.) value of the
aperture diaphragm affects the image contrast.
Increasing or reducing this value one can vary
resolution, contrast and depth of focus of the
image.
• With low contrast specimens pull the lever ③
(Fig. 30) to slightly close the aperture diaphragm.
If necessary, remove on eyepiece and, looking
into empty sleeve, adjust the diaphragm's lever
in order to obtain an image like the one in Fig. 31.
②
③
Page 14
Fig. 27
①
Fig. 28
Fig. 29
Fig. 30