Optika Italy B-1000 Serie Manuel D'utilisation page 27

13. Use of universal condenser for Brightfield / Darkfield / Phase contrast
Universal condenser provided with B-1000PH allows observation in brightfield, darkfield and phase contrast.
Observation mode
Phase contrast 10x
Phase contrast 20x
Phase contrast 40x
Phase contrast 100x
13.1 Brightfield observation (BF)
1. Rotate the condenser turret to insert the "BF" position.
2. Now repeat the steps described in the procedure "Brightfield (transmitted light) observation procedures".
13.2 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 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.
• While observing in darkfield, it could be useful to raise the condenser from the normal position to obtain a more
homogeneous illumination. This is not a defect.
F F ig. 44 ig. 44
F ig. 46 F ig. 46
Brightfield
Darkfield
F F ig. 47 ig. 47
Condenser turret position
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BF (Fig. 44)
DF (Fig. 45)
10/20 (Fig. 46)
10/20 (Fig. 46)
40 (Fig. 47)
100 (Fig. 48)
F ig. 45 F ig. 45
F ig. 48 F ig. 48