Leica DMI4000B, DMI3000B, DMI6000B manual Start-up

7. Start-up

field of view. The black edges of the image should have the same distance to the outer edge of the field of view on all sides. If not, recenter the image with the centering screws. Adjust the height of the condenser until the edges are sharp. Now open the field dia- phragm until the image fills the entire field of view and the black edges have disappeared completely (91.d).

¥The last step is the adaptation of the contrast settings. To improve the contrast, close the aperture diaphragm Ð if you close it too far, however, the resolution of the image details will deteriorate.

To see the aperture diaphragm, remove an eyepiece tube and look directly into the tube. Your eye should be around 10 to 20 cm from the tube. Change the size of the aperture dia- phragm until its image is clearly visible in the pupil of the objective.

¥Set the aperture diaphragm to cover 2/3 to 4/5 of the pupil diameter. You will now have the optimal balance between resolution and con- trast.

Fig. 90 Condenser centering

1Centering openings

2Height adjuster

3Prism and phase ring centering

2 1 2

3

Fig. 91 Koehler Illumination

aField diaphragm not focused, not centered

bField diaphragm focused, but not centered

cField diaphragm focused and centered Diameter is too small, however

dIllumination field diameter = visible field diameter (Koehler illumination)

1

ab

3

cd

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