Aperture Diaphragm - Optika Italy ECOVISION Serie Mode D'emploi

8.5

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.
Move the diaphragm ring ① (Fig. 10) on the value
corresponding to the objective in use. In this case
the optimal setting of the condenser is achieved.
• With low contrast specimens set the numerical
aperture to about 70%-80% of the objective's
N.A. If necessary, remove on eyepiece and, look-
ing into empty sleeve, adjust the condenser's dia-
phragm in order to obtain an image like the one
in Fig. 11.
①
APERTURE
DIAPHRAGM
FIELD OF VIEW
Page 11
F ig. 10 F ig. 10
70-80%
30-20%
F ig. 11 F ig. 11