Use Of Condenser For Brightfield / Darkfield / Phase Contrast (Optional); Brightfield Observation (Bf); Darkfield Observation (Df) - Optika Italy B-1000 Serie Bedienungsanleitung

12. Use of condenser for Brightfield / Darkfield / Phase Contrast (optional)
Universal condenser provided with B-1000 allows observation in brightfield, darkfield and phase contrast.
12.1 Brightfield observation (BF)
1. Rotate the condenser turret to insert the "BF" position.
2. Now repeat the steps described in the procedure "Brightfield observation procedures (transmitted light)".
12.2 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 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.
• When 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. 52
Fig. 54
Observation mode
Brightfield
Darkfield
Phase contrast 10x
Phase contrast 20x
Phase contrast 40x
Phase contrast 100x
Fig. 55
Condenser turret position
BF (Fig. 52)
DF (Fig. 53)
10/20 (Fig. 54)
10/20 (Fig. 54)
40 (Fig. 55)
100 (Fig. 56)
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Fig. 53
Fig. 56