Leica DMLB Bedienungsanleitung Seite 41

Operation of objectives
Immersion objectives*
OIL: only use optical immersion oil (30.4) of DIN/
ISO standard. Cleaning → p. 62. Lettering → p.
27 – 28 and p. 41.
W: Water immersion, used distilled water if
possible.
IMM: Universal objective for water, glycerine or
oil.
To immerse: Lower the stage or turn the
objective slightly out of the light path, apply 1 – 2
drops of immersion oil to the specimen, taking
care to avoid bubbles.
!
Attention:
Focus carefully, as the working distance of
immersion objectives is usually extremely short.
Be careful with objectives with front locking
device!
Locking of objectives
Some immersion objectives (identified by a
knurled grip, Fig. 25) can be shortened by
pushing in the front part by about 2 mm and
rotating slightly. This stops any remaining drops
of immersion liquid from wetting objects and
other objectives when the nosepiece is turned.
!
Attention:
This locking device must be released before the
immersion objective is used again, as otherwise
the spring mechanism protecting the specimen
and the objective is inactive and the other
objectives are not parfocal with the immersion
objective.
CORR objectives
Special objectives which can be adjusted to dif-
ferent coverglass
correction mount (not illustrated) roughly to an
average or estimated value by turning the knurl.
Focus the specimen (→ Fig. 25).
Adjust the correction mount until you obtain
optimum contrast, possibly refocusing with the
fine drive. This setting may be extremely difficult
with low-contrast or featureless specimen
areas.
Colour coding of objectives
As per DIN/ISO standards, the magnification of
each objective is indicated by a colour ring:
100x 63x 40x 25x
125x 50x 32x
150x
160x
white dark light dark
blue blue green
Immersion objectives have a second coloured
ring (Fig. 25) further down:
black Oil or Imm (= universal objective
for oil, water, glycerine)
white water
orange glycerine
thicknesses: set
16x 10x 6.3x 4x
20x 5x
light yellow orange red brown
green green
the
2.5x 1.6x
grey
41