5
COVER GLASS -
thin glass cut in circles, rectangles or squares, for
covering the specimen, usually a thickness of 0.15 to 0. I7mm. 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 Norman) an international optical standard for
the manufacturing of most quality microscope lenses. Many DIN lenses
will be interchangeable from one DIN microscope to another.
EYE POINT or EYE RELIEF
– the distance from the eyepiece lens to your
eye where a full field of view can be seen.
FIELD OF VIEW -
the area of the object 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 converge 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, objectives with 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 has to be made when an objective of one
power is substituted for another. The DIN objectives on your Swift
M3600 Series Microscope are parfocaled at the factory to a standard
45mm distance, so that only a slight turn of the fine adjustment is
required when a change is made from a lower to higher power.
RESOLVING POWER -
the ability of a lens to clearly separate fine detail.
Resolving power is directly proportional to the numerical aperture of
the optical system.
WORKING DISTANCE
– the distance from the lens of the objective to the
cover slip on the slide, when the specimen is in focus.
CORDLESS OPERATION (Cordless models)
The rechargeable battery should be fully charged for approximately 8
hours before the initial use. It can be charged by using the 4.5 volt A/C
adapter included with the microscope. The battery can be used to
