Aperture Diaphragm; Use Of Filters; Oblique Illumination - Optika Italy B-510 Serie Manual De Instrucciones

9.9.2 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.
• With low contrast specimens set the numerical
aperture value ① (printed on the condenser ring)
to about 70%-80% of the objective's N.A. (Fig. 29)
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. 27.
Example: with objective PLAN 40x / 0,65 set the
scale to 0.65 x 0.8 = 0,52
9.10 Use of filters
Insert the desired filter for the observation in the slot
placed in the left side of the illuminator (Fig. 30).
First click stop position leaves filter not inserted,
while second position inserts filter into the light path.
Filter
Blue Converts the source color temperature
Green Increase the contrast in black and white
Yellow Contrast filter for the observation of
wafers and semiconductors
Frosted white Reduces lighting irregularities by creat-
ing a homogeneous field of view

9.11 Oblique illumination

After focusing the specimen with the desired objective,
gently move the oblique illumination sliders (Fig. 31).
Stop sliding when a shadow begins to obscurate the
specimen. In this way an oblique illumination effect
can be achieved, that highlights reliefs and surface
defects of your specimen.
Application
to daylight
photography
Page 19
Fig. 29
①
Fig. 30
Fig. 31