Phase contrast set (4 eyepieces)

 The set contains a special condensor and a special phase contrast objective lens, which needs to be mounted on the microscope. The resulting image is very contrasty and is extremely useful to observe very thick specimen. Parts with different thickness can be easily seen. This method was first introduced by Frits Zernike in 1934.

Using the phase contrast method:
The illumination unit (Kohler-illuminator, with 5 holes phase contrast condensor and ring-diaphragm) requires very precise alignment. The specimen receives two kind of light. Different thickness of the speciment results in phase difference between light from the two sources. Usually performed with a 40x objective phase contrast lenses.
The kit contains the phase contrast condensor, the 4 objective lenses and the 4 different ring-diaphragm.

To adjust the microscope properly, check out this page: http://micro.magnet.fsu.edu/primer/java/phasecontrast/phasemicroscope/index.html