Centering The Brightfield Condenser; Effects Of The Field Diaphragm; Aperture Diaphragm - Optika Italy B-510 Serie Manual De Instrucciones

11.8 Centering the brightfield condenser
1. Place the specimen on the stage, insert 10x objective into the
light path and focus.
2. Insert the front lens of the swing-out condenser ①. (Fig. 17)
3. Rotate the field diaphragm ring
the arrow, to fully close the diaphragm.
4. Rotate the condenser height adjustment knob
edges of the diaphragm.
5. Rotate the two centering screws
the center of the field of view.
6. Gradually open the diaphragm. The condenser is centered
when the diaphragm image is symmetrical to the field of view.
7. In normal use, open the diaphragm until it circumscribes the
field of view.
11.9 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
circumscribes the field of view, in order to eliminate unnecessary
light to eyepieces. (Fig. 18)

11.10 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 set the numerical aperture value
(printed on the condenser ring) to about 70%-80% of the
⑤
objective's N.A.(Fig. 19). If necessary, remove on eyepiece and,
looking into empty sleeve, adjust the condenser's ring in order to
obtain an image like the one in fig. 20.
Example: with objective PLAN 40x / 0.65 set the scale to 0.65
x 0.8 = 0.52
in the direction showed by
②
to focus the
③
to bring the bright spot in
④
Page 14
①
③
APERTURE
DIAPHRAGM
FIELD OF VIEW
④
②
F ig. 17 F ig. 17
F ig. 18 F ig. 18
⑤
F F ig. 19 ig. 19
70-80%
30-20%
F ig. 20 F ig. 20