Zeiss Axioscope 5, Instruction Manual

Page: 95 / 204

ZEISS 5 Operation | 5.4 Setting Up for Transmitted Light Techniques
5.4.4 Setting the Darkfield Contrast with an Immersion Oil Darkfield Condenser
Prerequisite
ü The microscope is operational.
ü An immersion oil darkfield condenser is installed [
}
73] .
ü An immersion oil objective is installed.
ü Low-power system, polarizer or Lambda plate are swivelled out of the beam path.
Procedure 1. Move the condenser up until the end stop.
2. Place a drop of immersion oil (without bubbles, if possible) on the center of the condenser
front lens.
3. Place the sample on the stage.
à The immersion oil disperses between the condenser and the sample holder.
4. Slightly move the mechanical stage back and forth to dissipate any air bubbles in the im-
mersion oil.
5. Adjust the illumination intensity sufficiently bright.
6. Open the luminous-field diaphragm completely.
7. Swivel in an objective with small magnification (e.g. 10x).
8. Focus the sample.
9. Center the luminous-field diaphragm on the condenser carrier with the adjustment screws.
10. Focus the sample.
11. Place a drop of immersion oil on the sample.
12. Swivel in an immersion oil objective.
13. Focus the sample.
14. Close the luminous-field diaphragm until the end stop.
15. Lower the condenser until the edge of the field diaphragm appears sharp (luminous-field di-
aphragm focus level).
16. Center the field diaphragm on the condenser carrier with the adjustment screws.
à
The luminous field diaphragm appears only as a circle segment on the edge of the view-
ing field due to the high magnification of the immersion oil objective. As a result, the fo-
cusing and centering of the field diaphragm must be repeated.
The field diaphragm is centered properly, when the edge of the luminous field diaphragm
is centered or equidistant from the viewing field edge.
17. If the light intensity is too low, open the luminous-field objective slightly.
18. For a sharply focused sample, open the sharply set field diaphragm enough to make the
edge of the diaphragm disappear from the field of view.
19. Adjust the focus level of the condenser with the knurled knob for vertical adjustment to im-
prove the contrast.
20. For immersion oil objectives with an iris diaphragm, the contrast can be further optimized
by turning the adjustment of the iris diaphragm.
Instruction Manual ZEISS Axioscope 5, Axioscope 5/7 MAT | en-US | Rev. 13 | 430035-7344-001 95