1. Using the Swing out Condenser
When using the low magnification objective, turn out the condenser, and let it away from the light
path. While using the high magnification objective, turn it into the light path.
2. Adjusting the Aperture Diaphragm
The aperture diaphragm is designed for the adjustment of the numerical aperture , not for the
brightness. Generally, reducing the diaphragm opening to 70- 80% of the N.A. value of the respective
objective will provide an image of acceptable quality. If you want to observe the image of the aperture
diaphragm, remove one eyepiece and look through the tube. You will see a dark circle encroaching on
the bottom of the tube.
