Objectives - Zeiss Axioskop 2 plus Operating Manual

Carl Zeiss
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.
When working with the microscopes, the total magnification should not drop below or exceed the range
of useful magnification. The range of useful magnification was defined by Ernst ABBE as 500 to 1000
times the numerical aperture of the used objective. No further details are resolved above that limit. The
range of useful magnification for an objective with a numerical aperture of 0.25 is between 125 and
250x accordingly.
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).
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 plus
Axioskop 2 mot plus
dark white
blue
100x;
150x
B 40-075 e 10/03