Leica DMI3000B Bedienungsanleitung Seite 75

7. Start-up
this with a variety of field diaphragm settings
until you get a clear, sharp image (91.b). This
may take a while!
• To center the sharp image, insert the
centering keys in the openings provided at ei-
ther side of the top part of the condenser
(90.1). Move the image into the center of the
field of view (91.c). Next, open the field dia-
phragm until the image fills nearly the entire
field of view. The black edges of the image
should have the same distance to the outer
edge of the field of view on all sides. If not,
recenter the image with the centering
screws. Adjust the height of the condenser
until the edges are sharp. Now open the field
diaphragm until the image fills the entire field
of view and the
disappeared completely (91.d).
Fig. 90 Condenser centering
1 Centering openings
2 Height adjuster
3 Prism and phase ring centering
2 1
72
black edges
2 1
3
• The last step is the adaptation of the contrast
settings. To improve the contrast, close the
aperture diaphragm – if you close it too far,
however, the resolution of the image details
will deteriorate.
To see the aperture diaphragm, remove an
eyepiece tube and look directly into the tube.
Your eye should be around 10 to 20 cm from
the tube. Change the size of the aperture dia-
phragm until its image is clearly visible in the
pupil of the objective.
• Set the aperture diaphragm to cover 2/3 to 4/5
of the pupil diameter. You will now have the
optimal balance between resolution and con-
trast.
have
Fig. 91 Koehler Illumination
a Field diaphragm not focused, not centered
b Field diaphragm focused, but not centered
c Field diaphragm focused and centered
Diameter is too small, however
d Illumination field diameter = visible field diameter
(Koehler illumination)
3
a
c
b
d