Motic B3 Serie Manual De Instrucciones página 7

E. Köehler illumination.
The ideal level of illumination when all illumination elements are brought into proportion,
basically, by the condenser and the field diaphragm.
1. Focus on a sample with the 10X objective (5)..
2. Close the field diaphragm (11) turning the ring situated on the illuminator (19), until it
appears in the field of vision.
3. Next, focus the field diaphragm, moving the condenser (10) using its focusing control
(Fig. 1). Do not use the coarse (16) or the fine focus control knobs (17).
NB: The focus of the field diaphragm is not completely sharp, although it can be
adjusted to the maximum possible.
4. Center the condenser using the locking and centering screws (Fig. 2). As a
consequence, the field diaphragm will be centred.
5. Once field diaphragm is focused and centred, open the diaphragm just enough so
that the field of vision disappears. It must not be fully opened if optimum illumination
is to be obtained.
NB: For each objective used, the field diaphragm must be opened to a different
degree. If anything irregular appears in the field of vision, an element of the
illuminator or filter for example, appears in focus. Move the condenser just enough to
remove it from view.
F. Adjusting the opening diaphragm.
The opening diaphragm (9) must not be used to regulate light intensity. Its function is to
obtain the best resolution possible of the object, and proportion best image contrast. The
less the iris is opened, the better the image contrast, although reducing the opening too
much will worsen image contrast. The best means of finding the best image contrast is to
experiment with the size of the opening. Suggested apertures (openings) are as follows:
OBJECTIVE
4X
10X
40X
100X
G. Changing magnification.
1. Position the 10X objective (4) in the optical path.
2. This microscope arrives parfocalised, although it is possible that small differences exist
between objectives. If so, readjust slightly using the fine focus knob (19).
3. When the 40X and 100X objectives are changed, it must be done with extreme care, in
particular making sure that the objectives do not make contact with the slide as this could
damage the objective front lens.
4. To obtain maximum resolution with the 100X objective, it is necessary to apply immersion oil
between the slide and the front lens of the objective.
a. Use a very small amount of immersion oil, a tiny drop should be enough.
IRIS APERTURE
Totally closed to 1/8 open.
From 1/8 to 1/4
From 1/4 to 1/2
From 1/2 to 3/4
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