Centering The Condenser; Aperture Diaphragm - Optika Italy B-383 Serie Manual De Instrucciones

10.8 Centering the condenser

• The condenser is mounted and pre-centered before ship-
ment from the factory.
• To remove the condenser, use a 1.5 mm Allen key and turn
the fixing screw on the right-hand side of the condenser hold-
er.
If re-centering is necessary, proceed as follow:
1. Insert the 5x objective into the optical path (if the 5x objective
is not available, use the lower magnification objective).
2. Focus the specimen.
3. Close the aperture diaphragm using the ① dial, moving the
dial towards the "4" value for the 5X objective. (Fig. 17)
4. Raise the condenser to the end of its travel by turning the
condenser height adjustment screw ② on the left side of the
condenser holder.
5. Centre the condenser using the centering screws ③ until the
field of view is evenly lit (no lighter or darker areas within the
field of view).
6. Then open the diaphragm completely.

10.9 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.
1. Move the aperture ring ① (Fig. 18) to the value corresponding
to the objective in use. You can move the dial to lower or
higher values to adjust the observation to your preference.
• With low contrast specimens set the numerical aperture
value (printed on the condenser ring) to about 70%-80% of
the objective's N.A. 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. 19.
②
①
①
APERTURE
DIAPHRAGM
FIELD OF VIEW
Page 13
③
F ig. 17 F ig. 17
F ig. 18 F ig. 18
70-80%
30-20%
F ig. 19 F ig. 19