5
DIN
– (Deutsche Industrial Normen originally Deutsches Institut für
Normung). A German standard for the manufacturing of microscope
lenses.
EYE POINT or EYE RELIEF
– the distance from the eye lens of the
eyepiece to your eye where a full field of view is seen.
FIELD OF VIEW -
the area of the object that is seen when the image
is observed. It may range in diameter from several millimeters to
less than 0.1mm.
FOCAL LENGTH
- parallel rays of light after refraction through a
lens will be brought to a focus at the focal point. The distance from
the optical center of the lens to the focal point is the focal length.
NUMERICAL APERTURE (NA)
– a measure of an objective’s light
gathering capabilities. The concept may be compared to the F-stop
in photographic lenses. Generally speaking, N.A. values of less than
1.00 are "Dry" objectives. Values of 1.00 or greater require oil as a
medium. Please note that condensers are part of the optical system
and are also assigned an N.A. value. That value must be at least as
high as that of the highest objective used.
PARFOCAL
– a term applied to objectives and eyepieces when
practically no change in focus is needed when changing objectives.
The objectives on your microscope are parfocalized at the factory
so that only a slight adjustment of the fine focus knob is needed to
maintain focus when switching magnification.
RESOLUTION or RESOLVING POWER
– the ability of a lens to define
the details of the specimen at a maximum magnification. This is
governed by the NA (Numerical Aperture) of the lens. For example,
a 40X objective with NA 0.65 has a maximum resolving power of
650X, equal to 1000 times the NA. This rule of NA x 1000 is true of
all achromatic objectives.
WORKING DISTANCE
– the distance from the lens of the objective to
the cover slip on the slide, when the specimen is in focus.
USING THE SWIFT M10L SERIES MICROSCOPE
Once you have learned the terminology and purpose of each
component of the microscope, use of the microscope is simple. By
6
following these steps, you will be able to begin studying specimens
quickly and easily.
1.
Open the slide holder of the mechanical stage by pressing the
slide holder finger lever, and carefully place the slide against
the fixed side and back edge of the mechanical stage. Now
slowly release the slide holder finger lever allowing the “finger”
to hold the slide in place.
2.
Align the specimen under the objective lens by using the
adjustment knobs under the mechanical stage. The bottom knob
moves the slide from right/left while the top knob adjusts the
slide from front/back. These knobs allow for precise movement
and scanning of the slide.
3.
Rotate the nosepiece to place the lowest power objective (4XD)
over the specimen. Be sure the objective “clicks” into position.
(If you do not have a Swift M10L with Binocular Head please omit
step 4-5.)
4.
Adjust the interpupillary distance of the Seidentopf binocular
head for a comfortable view. Adjust the eyepiece tubes of the
binocular head by moving the eyepiece tubes in an arc motion
to the position where one perfect circle can be seen in the field
of view.
5.
For increased viewing comfort when using the Binocular Head,
use the left eye diopter adjustment to compensate for the
differences between the user’s eyes. Set the adjustable left eye
diopter at zero. Close your left eye and focus with your right
eye only by using the coaxial focusing knobs. Now using your
left eye only (close your right eye), adjust the diopter ring until
a clear image is seen. Now the binocular head is set for you to
observe the specimen.
6.
While viewing through the eyepiece, rotate the coarse focus
knob to bring the specimen into focus. This should be done
slowly and carefully.
7.
To adjust the contrast of the specimen, open the iris diaphragm
to its largest aperture. If additional contrast is required to
permit accurate viewing of the specimen, the diaphragm should
be slowly closed until the details of the specimen are sharply
defined. Be careful not to close the aperture too much, as you
may be achieving a higher contrast, but the fine structure of the
image may be destroyed. Reducing the aperture increases the
contrast and depth of focus, but it also reduces resolution and
