Diopter Adjustment; Condenser; Numerical Aperture Setting; Phase Rings Centering (Models B-380Ph) - Optika Italy B-380 Serie Manuel D'instructions

4.0 USING THE MICROSCOPE
4.6

Diopter adjustment

Turn the dioptric adjustment ring on the left eyepiece to the zero position. Turn the coarse focus knob
in order to focus the slide with an objective with low magnification. Adjust the fine focus knob until you
obtain a clear and defined picture observing with the right eye, and then act on the left dioptric com-
pensation ring observing with the left eye. When the image appears in focus, choose the necessary
objective with the revolving nosepiece.
4.7

Condenser

Raise or lower the condenser through the knob (4) to obtain a clear and uniform illumination of the
sample.
To center the condenser: completely close the iris diaphragm (3). Using the condenser centering
screws (2), move the diaphragm in the center of the field of view. Then gradually expand the dia-
phragm until it is tangent to the edges of the field of view. If necessary, you can perform an additional
adjustment.
The condenser is centered when the edges of iris diaphragm are tangent to the field of view.
4.8

Numerical aperture setting

The value of the numerical aperture (N.A.) of the diaphragm is an indication of the contrast of the il-
lumination system. Matching the value of illumination system's N.A. with that of the objective ensures
the best results in terms of contrast and image quality. To set the numerical aperture of the Illuminator,
adjust the opening of the iris diaphragm (3). In this way you control contrast and image resolution. For
samples with low contrast set the iris to about 75% of the value of the objective's numerical aperture.
4.9

Phase rings centering (models B-380PH)

For models equipped with phase contrast set, you have to perform the centering of the phase rings.
Remove an eyepiece from the head and insert the centering telescope in the empty tube.
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