The basic usage of dark field microscope is as follows
1. Install a dark field condenser (or use a thick black paper to make a light shield and place it under the condenser of an ordinary microscope to obtain dark field effects).
2. Choose a strong light source, usually with a microscope light to prevent direct light from entering the objective lens.
3. Add a drop of cedar oil between the condenser and the glass slide to avoid total reflection of the illuminating light on the condenser, failing to reach the object to be inspected and dark field illumination.
4. Perform center adjustment, that is, move the condenser horizontally so that the optical axis of the condenser and the optical axis of the microscope are strictly on a straight line. Lift and lower the condenser, align the focal point of the condenser (the apex of the conical beam in Figure 1-2) to the object to be tested.
5. Select the objective lens corresponding to the condenser, adjust the focal length, and operate according to the method of ordinary microscope.
