Centering The Field Diaphragm (Fs); Effects Of The Field Diaphragm; Centering The Aperture Diaphragm (As) - Optika Italy IM-5 Serie Manual De Instrucciones

10.10 Centering the field diaphragm (FS)
1. Move the selector on the reflected light illuminator in the
position "BF". (Fig. 21)
2. Place the specimen on the stage, insert 10x objective into the
light path and focus.
3. Completely pull out the field diaphragm lever ① to fully close
the diaphragm. (Fig. 29)
4. Using the provided Allen wrench use the two centering
screws ② to bring the bright spot in the centre of the field of
view. (Fig. 29)
5. Gradually open the diaphragm. The diaphragm is centered
when the diaphragm image is symmetrical to the field of
view. (Fig. 30)
6. In normal use, open the diaphragm until it circumscribes the
field of view.
10.11 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. 30)

10.12 Centering the Aperture Diaphragm (AS)

1. Move the selector on the reflected light illuminator in the
position "BF". (Fig. 21)
2. Completely pull out the aperture diaphragm lever ③ to fully
close the diaphragm. (Fig. 31)
3. Remove one eyepiece.
4. While looking into the empty eyepiece sleeve, use the
provided Allen wrench into the centering screws ④ to bring
the bright spot in the centre of the field of view. (Fig. 31)
5. The illuminator is centered when the diaphragm image is
symmetrical to the field of view.
• 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 move the diaphragm lever to
about 70%-80% of the objective's N.A. If necessary, remove
on eyepiece and, looking into empty sleeve, adjust the AS
lever in order to obtain an image like the one in Fig. 32.
APERTURE
DIAPHRAGM
FIELD OF VIEW
Page 17
②
①
F ig. 29 F ig. 29
F ig. 30 F ig. 30
④
③
F ig. 31 F ig. 31
70-80%
30-20%
F ig. 40 F ig. 40
F F ig. 32 ig. 32