Optika Italy B-1000 Serie Manual De Instrucciones página 15

9.12 Centering the condenser
1. Place the specimen on the stage, insert 10x ob-
jective into the light path and focus.
2. Insert the front lens of the swing-out condenser
①. (Fig. 24)
3. Rotate the field diaphragm ring ② clockwise, to
fully close the diaphragm.
4. Rotate the condenser height adjustment knob ③
to focus the edges of the diaphragm.
5. Rotate the two centering screws ④ to bring the
bright spot in the centre of the field of view.
6. Gradually open the diaphragm. The condenser is
centred when the diaphragm image is symmetri-
cal to the field of view.
7. In normal use, open the diaphragm until it circum-
scribes the field of view.
9.13 Effect of field diaphragm
Field diaphragm adjusts the illuminated area to ob-
tain a high contrast image.
Set the diaphragm according to the objective in use
until it circumscribes the field of view, in order to elim-
inate unnecessary light to eyepieces. (Fig. 25)
9.14 Aperture diaphragm
• The Numerical Aperture (N.A.) value of the ap-
erture diaphragm affects the image contrast. In-
creasing or reducing this value one can vary res-
olution, contrast and depth of focus of the image
• With low contrast specimens set the numeri-
cal aperture value ⑤ (printed on the condenser
ring) to about 70%-80% of the objective's N.A.
(Fig. 26). If necessary, remove one eyepiece and,
looking into empty eyepiece sleeve, adjust the
condenser's ring in order to obtain an image like
the one in Fig. 27.
Example: with objective PLAN 40x / 0.65 set the
scale to 0.65 x 0.8 = 0,52
③
①
②
APERTURE
DIAPHRAGM
FIELD OF VIEW
Page 15
④
F ig. 24 F ig. 24
F ig. 25 F ig. 25
⑤
F F ig. 26 ig. 26
70-80%
30-20%
F ig. 40 F ig. 40
F F ig. 27 ig. 27