Nikon Eclipse E400 POL User Manual

3. Operation of Each Part
2. Condenser aperture diaphragm
Numerical
Aperture
00/0.17 WD 0.65
0.65 x 0.7 - 0.8 2 0.455 - 0.52
Orthoscopic Microscopy
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
appropriate 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/0.65 means that the magnification is 40x and the numerical aperture is
0.65.
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 using the Bertrand lens
Insert the Bertrand lens into the optical path (by placing in position "B"). Turn the diaphragm
control ring to stop down the aperture diaphragm to its minimum setting. Turn the Bertrand.
lens focus ring to focus on the aperture diaphragm. Turn the diaphragm control ring to adjust.
the aperture diaphragm. (This is normally adjusted to 70-80% of the field of view.)
Conoscopic Microscopy
In the case of conoscopic microscopy, the condenser aperture diaphragm functions as a field
diaphragm on the conoscopic image surface. Stop down the diaphragm until it circumscribes the
circumference of the field of view of the conoscopic image (pupil of the objective).

Nikon Eclipse E400 POL Specifications

General

Brand	Nikon
Model	Eclipse E400 POL
Category	Microscope
Language	English