Leica DM R Serie Mode D'emploi page 96

The field diaphragm must also be exactly
centred in the field of view (65.7) and the
aperture diaphragm (65.11/12) closed.
Remove the objective or objective nosepiece:
the reflection of the field diaphragm is reflected
in the centre of the field of view if the object
surface is aligned exactly horizontal.
Diaphragm module HC RF
With 2 illumination channels and interchangeable
diffusing screens for incident light BF, DF, POL,
ICR, FLUO.
Illumination channel I
(Diaphragm module fully pushed in)
For use in all incident light modes with
– variable iris aperture and field diaphragm
– oblique illumination
– switchable neutral density filter
Illumination channel II
(Diaphragm module pulled out as far as the 1st
clickstop)
For use in all incident light modes with
– fixed aperture and field diaphragm
– mount for focusing graticule
Illumination channel II offers the additional
advantage of fast, reproducible switching
between open and closed diaphragms e.g.:
If the diaphragm setting is to be retained when
switching between brightfield and darkfield.
For fast switching between high and low
objective magnifications.
Channel II is also advantageous for measure-
ments with fixed diaphragms, for colour assess-
ment of coatings and oxide films and for work
with the focusing graticule.
96
Diffusing screen pairs A and B
The diaphragm module HC RF is equipped with
an interchangeable pair of diffusing screens
(23b.9) to obtain optimally geneous illumination
both for visual observation and for video and
digital image processing.
Diffusing screen pair A is included in the
standard delivery and contains diffusing screen
1 with dense distribution for even mination over
a large field of view of 25 mm or 28 mm with the
DM RD HC.
Diffusing screen 2 with low distribution for
maximum illumination homogeneity, but over
a reduced field of view of max. 20 mm (video
and digital image processing). Diffusing screens
1 and 2 can be used in either of the two
illumination channels. To do this, remove the
diffusing screen pair, which are held by
magnetism, and turn by 180° so that the labelling
A, 1 2 is upside down.