Eee Nene Een Ena - Nikon ECLIPSE E600 Instructions Manual

§ 2. Condenser aperture diaphragm
Numerical
Plan 40X _ Aperture
40x /:0.75°
RE
©
-WD
22
0.75X0.7~0.8=0.525~0.6
The aperture diaphragm is important because it is related to the resolution, contrast, depth of focus
and brightness of the optical image. Turning the condenser aperture diaphragm ring changes the
size of the aperture diaphragm.
As the aperture diaphragm is stopped down, resolution and brightness are reduced while contrast
and depth of focus are increased. Conversely, as the aperture diaphragm is opened, resolution and
brightness are increased while contrast and depth of focus are reduced. It is not possible to adjust
one pair of characteristics without affecting the other. Generally, a satisfactory image with appro-
priate contrast can be obtained with an aperture setting that is 70% to 80% of the numerical aperture
of the objective. The numerical aperture is indicated on the barrel of each objective.
An indication of 40x/0.75 means that the magnification is 40x and the numerical aperture is
0.75.
If the aperture diaphragm is stopped down too far, the resolution is reduced; therefore, except when
viewing a nearly transparent specimen, we do not recommend stopping down the aperture to less
than 60% of the numerical aperture of the objective.
Adjusting the size of the aperture diaphragm according to the condenser scale
Since the condenser scale indicates the numerical aperture, adjust the aperture diaphragm ring
according to the scale. (Normally, the index on the aperture diaphragm ring should be aligned
with the scale line corresponding to 70% to 80% of the numerical aperture of the objective.)
Adjusting the size of the aperture diaphragm by using a centering telescope
(sold separately)
Remove one of the eyepieces and, by using a special adapter (sold separately), mount a centering
telescope in its place. Turn the aperture diaphragm ring to stop down the aperture diaphragm as
far as possible. While holding down the flange of the telescope, turn the eyepiece of the center-
ing telescope and focus on the aperture diaphragm.
Turn the aperture diaphragm ring to adjust the size of the aperture diaphragm. (Normally, the
aperture diaphragm should be adjusted so that it is about 70% to 80% of the size of the field
being viewed.)
Remove the centering telescope and adapter, and then re-fit the eyepiece.
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