Tube: Where the eyepieces are dropped in. Also, they connect the eyepieces to the objective lenses.

Base: The bottom of the microscope—what the microscope stands on.

Arm: Structural element that connects the head of the microscope to the base.

Stage: The flat platform that supports the slides. Stage clips hold the slides in place. If your
microscope has a mechanical stage, the slide is controlled by turning two knobs instead of having
to move it manually. One knob moves the slide left and right, the other moves it forward and
backward.

Illuminator: A steady light source (110 volts in the US) that shines up through the slide. Mirrors are
sometimes used in lieu of a built-in light. If your microscope has a mirror, it is used to reflect light
from an external light source up through the bottom of the stage.

Nosepiece: This circular structure is where the different objective lenses are screwed in. To change
the magnification power, simply rotate the turret.

Objective Lenses: Usually you will find 3 or 4 objective lenses on a microscope. The most common
ones are 4X (shortest lens), 10X, 40X and 100X (longest lens). The higher power objectives (starting
from 40x) are spring loaded, which means that if they hit a slide, the lens will retract, preventing
damage to both the lens and the slide. All quality microscopes have achromatic, parcentered,
parfocal lenses. In addition, to get the greatest clarity at high levels of magnification, you will need a
microscope with an Abbe condenser. Lenses are color coded and are interchangeable between
microscopes if built to DIN standards.

Rack Stop: This feature determines how far up the stage can go. Setting the rack stop is useful in
preventing the slide from coming too far up and hitting the objective lens.  Normally, this adjustment
is set at the factory, and changing the rack stop is only necessary if your slides are exceptionally thin
and you are unable to focus the specimen at higher powers.

Condenser Lens: Condenser lenses focus the light that shines up through the slide, and are useful
for attaining sharp images at magnifications of 400X and above. If the maximum power of your
microscope is 400X, a stage mounted 0.65 NA (or greater) condenser is ideal since it give you
greater clarity without having to be focused separately. However, if your microscope goes to 1000X
or above, focusable condenser lens with an N.A. of 1.25 or greater is needed. Most microscopes
that go up to 1000X come equipped with an Abbe condenser, which can be focused by moving it up
and down. The Abbe condenser should be set closest to the slide at 1000X, and moved further away
as the magnification level gets lower.

Diaphragm or Iris: The diaphragm or iris is located under the stage and is an apparatus that can be
adjusted to vary the intensity, and size, of the cone of light that is projected through the slide. As there
is no set rule on which setting to use for a particular power, the setting depends on the transparency
of the specimen and the degree of contrast you desire in your image.

What to look for when purchasing a microscope: If you want an instrument that can provide you
with crisp, high-quality images at high resolutions, stay away from microscopes with plastic
components. Instead, look for a microscope that has a metal body and all glass lenses. Make sure
you purchase your precision instrument from a well-established dealer who will be around to help
you with technical problems in case you have issues with your microscope. At AmScope.com, we
pride ourselves on providing the best instruments at the lowest prices without sacrificing customer
service. Technical support is one simple phone call or email away.  
Invented by a Dutch spectacle maker
in the late 16th century, light
microscopes use lenses and light to
magnify images.  Although a
magnifying glass technically qualifies
as a simple light microscope, today’s
high-power—or compound—
microscopes use 2 sets of lenses to
give users a much higher level of
magnification, along with greater
clarity. The first set of lenses are the
oculars, or eyepieces, that the viewer
looks into; the second set are the
objectives, which are the lenses
closest to the object. Before
purchasing or using a microscope, it
is important to know the functions of
each part.


Eyepieces: The eyepieces are the
lenses at the top that the viewer looks
through; they are are usually 10X or
15X. To get the total magnification
level, multiply the magnification of the
objective used (ex: 10X eyepiece * 40X
objective = 400X total magnification).
microscope library > Microscope Parts and Functions
MICROSCOPE PARTS AND FUNCTIONS
Call Toll Free (888) 950-2888
Monday-Friday 8:00am-6:00pm PST   International: (909) 393 9488
American Scope
a division of iScope Corp, USA