Nikon DIAPHOT 300 Instructions Manual page 29

NOTE
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• Be sure to keep the condenser aperture diaphragm fully
opened when the system condenser turret unit is used for
phase contrast microscopy. (With the condenser aperture
diaphragm stopped down, the optical path is blocked.)
• Since the condenser aperture diaphragm of the ELWD
condenser is independent from annular diaphragm, its size will
not have any effect on the annular diaphragm.
• There is no condenser aperture diaphragm on SLWD
condenser.
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