Aperture Diaphragm - Optika Italy ECOVISION Serie Manual De Instrucciones

8.5

Aperture diaphragm

• The Numerical Aperture (N.A.) value of the aperture dia-
phragm affects the image contrast. Increasing or reducing
this value one can vary resolution, contrast and depth of fo-
cus 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, looking into empty sleeve, adjust the con-
denser's diaphragm 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