Use Of Universal Condenser For Brightfield/Darkfield/Phase Contrast; Brightfield Observation (Bf); Darkfield Observation (Df) - Optika B-380 Series Bedienungsanleitung

10. Use of universal condenser for brightfield/darkfield/phase contrast
Universal condenser provided with B-382PH ALC, B-383PH, B-382PHI-ALC, B-383PHI allows
observation in brightfield, darkfield and phase contrast.
OBSERVATION MODE
Phase contrast (10x)
Phase contrast (20x)
Phase contrast (40x)
Phase contrast (100x)
10.1 Brightfield observation (BF)
Rotate the condenser turret to insert the "BF"position. Now repeat the steps described in the procedure "Summary
of brightfield observation procedures" at page 18.
10.2 Darkfield observation (DF)
1. Rotate the condenser turret to insert the "DF" position.
2. Open the aperture diaphragm.
3. Place a specimen on the stage and focus.
4. Observing into eyepieces raise or lower the condenser until a homogeneous illumination of the specimen
can be achieved, thus obtaining a proper darkfield effect.
• Darkfield requires a huge amount of light. Switching from darkfield to brightfield, one could be
dazzled. Do not keep your eyes on the eyepieces when moving the condenser turret from DF to BF.
• "Dry" darkfield observation, that is, without the use of oil, is only possible with objectives with N.A.
lower than 0,7.
• Observing in darkfield, it may be necessary to raise the condenser from the normal position to obtain
a more homogeneous illumination. This is not a defect.
Fig. 25
Brightfield
Darkfield
Fig. 23
Fig. 26
Page 23
Fig. 24
Condenser Turret position
BF (Fig. 23)
DF (Fig. 24)
10/20 (Fig. 25
10/20 (Fig. 25)
40 (Fig. 26)
100 (Fig. 27)
Fig. 27