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4
Brightfield microscopy
•
Set the Phase annular diaphragm slider in the centered open position.
•
Bring the specimen image into focus.
•
Adjust the opening of the field of view diaphragm, for normal observation the size of the diaphragm
should be just outside the edge of the field of view.
•
The condenser aperture diaphragm is provided for adjusting the numerical aperture (N.A.) of the
illuminating system of the microscope. It is important because it determines the resolution of the image,
contrast, depth of focus and brightness.
•
Closing down the aperture diaphragm will lower the resolution and brightness but increase the contrast
and depth of focus. By closing down the N.A. of the condenser to 2/3 of the N.A. of the objective, an
image of suitable contrast will be obtained.
5
Phase-contrast microscopy
•
Phase contrast objectives are label
ed “Ph”
•
Fully open the aperture diaphragm. Position the Phase annular diaphragm slider to 10 -20. Set slider to
40 when using a 40x (Ph3) objective. See picture below.
•
Bring the 10x (Ph1) objective into optical path.
