Swift M10D Series, Use And Care Manual

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magnification and convert the image into a field of view easily seen by the
human eye.
COVER GLASS
– thin glass cut in circles, rectangles, or squares, for
covering the specimen (usually a thickness of 0.15 to 0.17mm). The
majority of specimens should be protected by a cover glass, and must be
covered when using 40XRD or 100XRD objectives.
DEPTH OF FOCUS
– the ability of a lens to furnish a distinct image
above and below the focal plane. Depth of focus decreases with the
increase of numerical aperture or with the increase of magnification.
DIN
– (Deutsche Industrial Normen
originally Deutsches Institut für
Normung). A German standard for the manufacturing of microscope
lenses. DIN lenses will be interchangeable from one DIN microscope to
another.
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-valve 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