Dark Field (Tl) - Leica Microsystems DMI3000 B Mode D'emploi

8. Operation

8.2.3 Dark Field (TL)

Note:
The maximum usable objective aperture for dark
fi eld is for the condenser S1 0.70 and for the con-
denser S23/S28 0.40.
Leica DMI3000 B:
• If necessary, adjust the TL bright fi eld position
at the fi lter slider.
• Select a dark fi eld objective.
• Select the suitable dark fi eld stop on the con-
denser.
• Open the aperture of the condenser complete-
ly.
• Remove all other optical components such
as analyzers, polarizers or IC prisms from the
beam path.
• Insert a dark fi eld specimen.
• Set the brightness at the light potentiometer
• Focus the image with the focus wheels.
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Leica DMI4000 B and Leica DMI6000 B:
• Use the TL/IL function button to switch to
transmitted light (TL).
• Select the DF (dark fi eld) contrast method
by pressing the variable button BF.
Alternatively: press the variable button
CHANGE TL .
(For details on button assignments, please see
the identifi cation sheet.)
DF will appear on the LeicaScreen.
Motorized condensers will now switch to the
dark fi eld ring. Coded condensers must be
switched manually.
• Insert a transmitted light specimen.
• Rotate an appropriate objective into place.
• Focus the image with the knob on the Smart-
Move or the focusing wheel and adjust the in-
tensity with the INT function buttons.
When selecting the dark fi eld method, the aper-
ture diaphragm is opened fully and can not be
adjusted.