Leica DM L, Instructions Manual

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Due to basic physical principles and the
physiology of the human eye, all imaging
techniques, not only the microscope, are
subject to limitations in performance. For proper
use of the microscope you should therefore
know and observe the following information.
Objectives
The DM L microscope series is based on tube
length
∞
(infinity) and a focal length of the tube
lens of f = 200 mm. Therefore, only objectives
with the engraving
∞
(Fig. 25) and M25 or M32
thread may be used.
Objective labelling
Examples (see also Fig. 25) and meaning of the
symbols:
∞
/ –
∞
/0.17
∞
/0/D
C PLAN 10x/0.22 C PLAN 40x/0.65 N PLAN 50x/0.75
Performance parameters of objectives
∞
Objective for infinite tube length (
∞
).
–
The objective can be used with and without a
coverglass.
0.17
The objective may only be used with a
coverglass of the standard 0.17 mm thickness.
Use without a coverglass or with a coverglass of
a very different thickness will result in a distinct
drop in performance, especially for objectives
with high apertures,
→
p. 41.
0
Use without a coverglass, e.g. for cell smear
specimens, incident light.
Fig. 25 Objectives, examples
1 Brightfield objective, 2, 3 POL objectives, 4 Phase contrast immersion objective, 5 Immersion objective with iris diaphragm,
6 CORR objective for inverted microscopes, 7 BD objective for incident light brightfield and darkfield (M25 thread)
Some immersion objectives with a knurled ring have a front part which can be pushed up and “locked” with a small rotational
movement. This device must be unlocked for observation! The sleeve of PL FLUOTAR and PL APO objectives can be rotated so
that the engraving can be read more easily.
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