Adjust the field diaphragm in the illuminator system so that light
centers directly on the diaphragm leaves of the microscope
STEP 2: Ensure that the specimen is still in focus.
STEP 3: Focus the substage condenser until the leaves of the iris
diaphragm come into focus.
STEP 4: Close the field diaphragm until no more than the field to be
examined is illuminated.
STEP 5: Remove the right ocular and examine the back lens of the
objective. The diaphragm of the condenser is now opened or
closed until the light just fills the back lens of the objective. When
this occurs, a thin silhouette of prismatic color may be seen at the
edge of the diaphragm.
STEP 6: Replace the ocular and the illumination should now be correct.
1-30. LIGHT INTENSITY
a. One of the most important considerations in parasitology work is the
application of light in the microscope. Without proper illumination and light intensity
parasitic identification forms can easily be missed.
b. The light intensity should be increased or decreased by the use of the neutral
density filter control. The iris diaphragm can be used if more or less light is required.
Do not move the substage condenser (condenser focusing knob) to adjust
the amount of light. This will destroy the critical illumination effect.
1-31. THE USE OF THE OIL IMMERSION OBJECTIVE
The oil immersion objective can be used to view extremely small objects. Follow
Adjust/focus the microscope on low power.
STEP 2: Rotate the nosepiece until no objective is in place.
STEP 3: Place a small drop of oil on the slide.
STEP 4: Rotate the nosepiece until the oil immersion objective is in place.
STEP 5: Focus the object carefully with the fine adjustment knob.