b. Focusing the Specimen.
STEP 1: Move the swing-out lens (under the microscope) out of the light
path (if the scope is so equipped).
STEP 2: Place the substage condenser in the extreme upper position.
STEP 3: Rotate the coarse focus adjustment counterclockwise to lower the
STEP 4: Use the fine focus knob to bring the specimen into sharp focus.
(a) Rotate the fine focus knob completely counterclockwise until it
reaches its stop.
(b) Rotate the knob back four to five turns clockwise while looking
through the oculars. The scope should be in focus.
c. Adjusting the Interpupillary Distance. Adjust the interpupillary distance by
using the thumb wheel.
Do not pull the oculars apart, this action may result in irreparable damage to
d. Focusing the Oculars.
STEP 1: Focus the specimen while looking through the right ocular and
adjusting with the fine focus knob.
STEP 2: Adjust the left ocular by turning the ocular focus knob.
Most microscopes are parfocal; that is, once the object is in focus with one
objective, the other objectives should be in focus with just a slight adjustment of the fine
1-29. KOHLER ILLUMINATION
Kohler illumination may be obtained once the preceding adjustments of the
microscope have been made. Since most of the confirmatory work in examining
parasitological specimens is usually accomplished by the use of the high power
objective, adjustment aimed at obtaining this type of illumination should be made using
the high power objective.