Objectives - Zeiss Axioskop 2 Manual

Fig. 1-3 Objective
Other labels:
Oil : oil immersion objective
Ph 2 : phase contrast objective with a green color ring and phase stop Ph 2
Color ring code for objective magnification
Color ring on black
objective
Magnification 1.25x
factor
The objective magnification multiplied with the eyepiece magnification (minimum 10x) results in the
visual overall magnification: e.g. 10 x 10 = 100x.
The numerical aperture x 1000, e.g. 0.25x1000 = 250x, is the highest useful magnification, i.e. no
further details are resolved above that limit.
The exact observance of the cover slip thickness of 0.17 mm is all the more necessary the higher the
numeric aperture of the objective. Therefore, certain objectives can be set for different cover slip
thickness (due to correction mount). For this, a specimen area is searched, and the position of the
correction ring where optimum focus and image contrast are obtained is determined (refocusing is
always required).
Immersion objectives are always insensitive to differences in cover slip thickness. When immersion
objectives are used, the air between the cover slip and the objective is replaced with a liquid, which is
1-12
INSTRUMENT DESCRIPTION

Objectives

brown red orange
2.5x 4x; 5x 6.3x
1.5 Objectives
The objectives are the optical centerpiece of the
microscope. The following is an example of how
objectives can be labelled:
Achroplan 10x/0.25 ∞ 0.17
where
10x : objective magnification, with a defined
color ring on the objective being allocated
to each magnification step (Zeiss color
code)
0.25 : numerical aperture
∞
: infinite image distance; these objectives
can only be used with ICS microscopes
from Carl Zeiss
0.17 : can only be used with cover slip thickness
D = 0.17 mm
or
−
: can be used with cover slip thickness D = 0
or 0.17 mm
yellow green light
blue
10x 16x;20x; 40x; 50x 63x
25x;32x
Axioskop 2 / Axioskop 2
dark white
blue
100x;
150x
B 40-075 e
MOT
06/98