Selecting A Condenser; Adjusting The Field Diaphragm - Nikon Eclipse 50i Instructions Manual

Selecting a Condenser

3.11
Objective
Achromatic/aplanat
magnification
condenser
1x x
2x x
4x x
10x to 100x
Note 1: The entire field of view may not be covered if a UW eyepiece is attached.
Note 2: Indoor lighting and light from other sources reflected from the surface of the
condenser lens may enter the field of view. If this happens, dim the indoor lighting
or find some way to keep strong extraneous light from striking the stage.
Note 3: Swing out the top lens before use.
Depending on the type of objective, the indicated numerical aperture of the objective may not be
achieved.
For example, when an objective with an N.A. of 1.4 is used, the maximum aperture of the
swing-out condenser or the Abbe condenser will be only about 65% of the objective's N.A., even
when the condenser aperture diaphragm is wide open.
Refer to the condenser operating manual for more information on phase contrast condenser.
3.12

Adjusting the Field Diaphragm

The field diaphragm controls the amount of
illumination falling on the area of the specimen
being viewed. Turning the field diaphragm knob
changes the size of the field diaphragm. For normal
observations, the size of the diaphragm should be
slightly wider than the boundary of the field of
view. Illuminating a broader area than necessary
will result in stray light entering the field of view,
generating flare and reducing image contrast.
Appropriate field diaphragm settings are
particularly important for photomicrography. In
general, good results will be obtained by stopping
down the field diaphragm to settings slightly wider
than the area to be reproduced within the photo
frame or monitor display.
Chapter 3 Individual Operations
3.11 Selecting a Condenser
Condenser ( : Optimum,
Swing-out Achromat
condenser condenser
x x
Note 3
x
Note 2
47
: Suitable, x: Not suitable)
Abbe Low-magnification
condenser condenser
Note 2
x
x
Note 1
x
Field diaphragm knob
1-100x
condenser
3