Olympus bx40 - Page 20

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Condenser Centration (Fig. 51, 52, 53, 54, 55)
. Turn the condenser height adjustment knob (D and raise the condenser
to its upper limit. (Fig. 34)
Focus on the specimen using the 10X objective.
* When using the U-SC swing-out condenser, move the front lens
into the light path.
Rotate the field iris diaphragm ring @ in the direction of the arrow to
reduce the aperture.
Turn the condenser height adjustment knob © to where the image of
the iris diaphragm is visible in sharp focus.
+ Turn the two condenser centering screws @ to move the image of the
field iris diaphragm to the center of the field of view.
Gradually open the field iris diaphragm. The condenser is properly centered
if the iris image is centered and inscribed in the field of view.
. During actual use, increase the field stop slightly so that its image is
just outside the field of view.
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Field iris diaphragm
Fig. 53
Field Iris Diaphragm (Fig. 53) |
The field iris diaphragm restricts the diameter of the beam of light
entering the condenser and thus excludes extraneous light, improving
image contrast. The diameter of the field iris should be adjusted for
objective power to the extent that it lies just outside the field of view.
(See “Compatibility of objectives and condensers” on the next page.)
When photographing specimens, stop the field stop down to where it
is somewhat larger than the firm format @ to obtain even better results.
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