9.2 Fluorescence
• Insert a suitable specimen and rotate an ap-
propriate objective into place.
• Focus the image initially in transmitted light if
appropriate.
• Switch on the incident light source at the ex-
ternal power unit.
• Open the shutter.
• Select an appropriate fluorescence filter
cube.
• Switch magnification changer, if present, to
factor 1x.
• Disengage the BG 38 filter if there is no dis-
turbing red background. Always engage the
filter for photography, however.
• Open the aperture diaphragm.
• Open the field diaphragm until the whole field
of view is just illuminated.
If necessary center the field diaphragm.
Fig. 65
Fluorescence illuminator with filter block changer, shutter,
BG38, field and aperture diaphragm
9. Contrast Methods
61