OPERATION
ZEISS
Illumination and contrast methods in transmitted light
Axiolab 5
82
430037-7444-001
05/2019
•
Close the luminous-field diaphragm (Fig. 4-3/
5
)
until it is visible (even if not in focus) in the field
of view (Fig. 4-3/
A
).
•
Turn the vertical control of the condenser drive
to lower the condenser until the edge of the
luminous-field diaphragm appears in focus
(Fig. 4-3/
B
).
•
Center the luminous-field diaphragm using the
two centering screws (Fig. 4-3/
4
) on the
condenser carrier (Fig. 4-3/
C
) and then open the
luminous-field diaphragm until the edge of the
diaphragm just disappears from the field of
vision (Fig. 4-3/
D
).
•
To adjust the aperture diaphragm (contrast),
remove an eyepiece from the eyepiece tube and
look into the tube with the naked eye. Set the
aperture diaphragm with the adjusting lever
(Fig. 4-4/
4
) to between 2/3 - 4/5 of the
diameter of the exit pupil of the objective
(Fig. 4-3/
E
). In most applications, this aperture
diaphragm setting provides optimal contrast at
almost ideal resolution, and is therefore the best
compromise for the human eye.
•
Reinsert the eyepiece into the eyepiece tube.
NOTE
Every change of objective will result in a change in specimen field size and objective aperture,
together with a possible slight change in centering, so that for optimal results the luminous-
field and aperture diaphragm adjustments must be repeated.
With objectives < 10x, the front lens of the condenser (if swivelable) must be swiveled out of
the beam path and the aperture diaphragm completely opened. For better contrast with such
large object fields, the luminous-field aperture should be closed to a certain extent.
Overclosing should be avoided so as not to impair the uniformity of the illumination of the
field of view.
Fig. 4-3
Microscope settings in transmitted
light brightfield microscopy
