Leica DM R Serie Mode D'emploi page 88

Choice of prisms
Choose the objective side prism (60.7) with the
letter indicated in the top line of the objective
engraving* (page 48 and on Optics data sheet),
e.g. A for pupil position A.
Additional numbers e.g. B
beamsplitting than the standard version (= B
for higher detection sensitivity.
Choose the condenser side prism (60.8) that
corresponds to the magnification of the
objective used, e.g. pos. 20/40 for objective 20x
(and 40x).
Swing in condenser top 0.90 S1, only swing out
condenser top for the 5x objective (only with
UCR/UCPR condenser; ICT is only possible with
the UCE condenser from objective 10x upwards).
Exactly set Koehler illumination (see page 69).
This is made easier by temporarily focusing a
stained specimen or the edge of the coverglass.
Setting ICT contrast
Carefully turn the objective-side prism turret
(60.7) to the left and right. Also adjust contrast
with the aperture diaphragm (48.21). Particularly
sensitive setting is possible with the λ/4 com-
pensator (57.1), which is inserted in the holder
under the condenser (60.9) and rotated
88
: Prism with greater
2
1
(objective prism roughly at the centre position).
Optimum contrast for specimens with parallel
structures can be obtained by rotating the stage
(48.8).
Colour contrast: Turn over the analyser, so that
the sign can be seen on the top. If using the 360°
),
rotatable analyser (30.1) colour contrasting is
carried out by placing a rotatable whole-wave
compensator (57.1) on the polarizer or pushing it
into the mount underneath the condenser (27.6)
and rotating.
Specimen preparation
ICT gives best results for unstained, relatively
thin, non-birefringent specimens. Interpretation
of birefringent specimens can be extremely
difficult, if not impossible. It may be helpful to
rotate the specimen to an optimum azimuth
position.
Specimen slides, coverglasses and embedding
resins of birefringent material may not be used.