64
Setting Koehler illumination
Turn the 10 x objective into the light path and
focus the specimen.
1. Turn the condenser disc (84.3) to the ”H“
clickstop position (H = Hellfeld= brightfield)
2. Close the field diaphragm (48.8)
3. Adjust the height of the condenser (82.3) until
the edge of the field diaphragm is sharply
focused.
4. Centre the field diaphragm with the two con-
denser centring screws (82.2) in the middle of
the field of view.
5. Open the field diaphragm until it just disap-
pears from the field of view.
6. The field diaphragm centration may need
slight readjustment when an objective is
changed.
The field diaphragm protects the specimen from
unnecessary warming and enhances the image
contrast. It is therefore only opened wide enough
to illuminate the observed or photographed field.
Superfluous light is kept away from the speci-
men.
Therefore, the field diaphragm should be read-
justed and adapted when the objective magnifi-
cation is changed.
Close the aperture diaphragm (84.4) until you
obtain the desired image contrast.
Fig. 84
Condenser 0.53 S23
1
Condenser base,
2
Condenser top 0.53 S23 (interchangeable),
3
Condenser disc,
4
Aperture diaphragm,
5
Filter holder,
6
Dovetail guide
Fig. 85
Condenser tops for condenser base (84.1)
1
Condenser top 0.53 S23,
2
Condenser top 0.90 S1,
3
Conden-
ser top P 1.40 OIL S1,
4
Spacer ring for assembly of 9.2 and 9.3
3
4
6
5
1
2
1
2
3
4
