Use Of Universal Condenser For Brightfield / Darkfield / Phase Contrast; Brightfield Observation (Bf); Darkfield Observation (Df) - Optika Italy B-1000 Serie Manual De Instrucciones

10. Use of universal condenser for Brightfield / Darkfield / Phase contrast
Universal condenser provided with B-1000PH allows observation in brightfield, darkfield and phase contrast.
10.1 Brightfield observation (BF)
1. Rotate the condenser turret to insert the "BF" position.
2. Now repeat the steps described in the procedure "Summary of brightfield observation procedures".
10.2 Darkfield observation (DF)
1. Rotate the condenser turret to insert the "DF" position.
• By inserting the darkfield ring, the aperture diaphragm opens automatically. This is a desired effect
and should not be considered a defect.
2. Place a specimen on the stage and focus.
3. 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 daz-
zled. 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. 46
Fig. 48
Observation mode
Brightfield
Darkfield
Phase contrast 10x
Phase contrast 20x
Phase contrast 40x
Phase contrast 100x
Fig. 49
Condenser turret position
BF (Fig. 46)
DF (Fig. 47)
10/20 (Fig. 48)
10/20 (Fig. 48)
40 (Fig. 49)
100 (Fig. 50)
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Fig. 47
Fig. 50