6
Identification markings on the objecti'ves
(Fig.
5)
1 Mechanical tube l
engt
h
The
di
stance
in
mm
from the ob
je
ctive sho
ulder
to the edge
of
the
tube
.
2 Coverglass
The
engraving
0.17
is the thick
ne
ss of the coverglass.
A
dash
(-) instead
of
a
number
indicates that
the
objective
can
be
us
ed for sp
ec
imens with or without a coverglass.
3
Field
Oatness
of
the objective
EF objectives a
re
systems with a more
or
less flat
fi
e
ld
of
view
of
up
to
18
mm intermediate image diameter.
PLAN
objectives are systems with a
flattened
fi
eld
of
vi
ew up
to 22.5
mm
interm
ed
iate
image
di
ame
ter.
Fig. 5 Objective identification
If
there
is no indica
tion
of
field
fl
at
tening,
the objecti
ve
is
an
achromat with optimum correction,
for
use with
up
to
18
field
of
vi
ew
inde
x.
4 Reproduction scale in the int
er
mediate image
Size ratio between the intermediate
im
age and the object, e.g.
10
:1
5 Numerical aperture
Physical identification
of
the objective's resolving power
6 Immersion medium
Immersion media can be, for example.o
il
.water (W) orglycer-
ine
(GLYC).
Th
e objective
must
always be used with
the
engraved immersion medium.
Bef
ore the immersion objective is focu
se
d, a drop
of
im
mer-
sion
medium
should
be
applied to
the
obje
ct
without
air
bub
bles.
7
Ph
ase cootrast objectives
Objectives with
ph
ase ring
for
phase contrast observation.
The
se objectives have
green
writing (w
ith
the
exception
of
achromats
with black sleeves).
The
label for the
condenser-
side
annular
stops necessary for
these
ob
jective
s (e.g.
PHACO
3) in a
slide
or
in
the
turret
platc
of
tbe
UKL
phase
contrast
condenser
(e.g.
PHACO
3= set
turret
plate
to 3) is also
to be found
on
th
e
phase
c
ontra
st obj
ec
tives.
8 Colo
ured
ring
indicating
the
ob
jective
magnification
9 Immersion objectives
