5
5. Position the objective turret until the 4x (smallest) objective lens “clicks” into position in the optical path. Note that
each time you change from one objective lens to another you should turn the turret until you hear the “click”, which
indicates that the lens is properly indexed in the optical path.
6. Swing moveable finger on slide holder outward. Place specimen slide (cover slip up) on top of stage surface against
fixed side of slide holder. Slowly release moveable finger until it makes contact with specimen slide.
7. Turn rheostat (dimmer) control in direction to reduce illumination brightness to about mid-point. Normally, brightness
will need to be reduced as magnification is reduced, and increased as magnification is increased. Experiment with
this adjustment until optimum resolution and contrast of specimen is obtained.
8. Locate lever beneath stage that controls the iris diaphragm. Move lever until iris diaphragm is about half open.
Normally, aperture of iris should become smaller for lower magnifications and larger for higher magnifications.
Experiment with this setting until optimum resolution and contrast of specimen is obtained.
9. While looking through the eyepiece, rotate coarse focusing knobs until specimen comes into focus. If image does not
appear in field of view, move specimen slide slightly until image appears in field of view.
10. Adjust fine focus controls until specimen is in sharp focus.
11. Changing magnification.
a. Magnification is changed by rotating objective turret until a different objective lens is moved into optical path.
Always turn turret until you hear the “click”, indicating that lens is properly indexed. Otherwise, you will not be
able to see anything when looking through the microscope.
Objective Specifications
Objective
N.A.
Color Code
Ring
Field of
View
Working
Distance
Magnification with
WF10X eyepiece
Din 4X
0.10
Red
4.5mm
18.5mm
40X
Din 10X
0.25
Yellow
1.8mm
6.4mm
100X
Din 40X retractable
0.65
Blue
0.45mm
0.5mm
400X
Din 100x retractable
1.25
White
0.18mm
0.06mm
1000X
b. Also note that each objective has a color ring, which permits you to instruct changes in magnification by referring
to an easily observed color rather than to a number.
c. The microscope has been parfocalled at the factory, which allows easy change from one magnification to another,
requiring little or no adjustment of the fine focus knobs.
d. As magnification is increased, the field of view (area of specimen seen through the microscope) will decrease.
That is why it is easier to find the specific area of interest on the specimen by starting with the lowest 4x objective
lens, before increasing magnification with the higher power objective lens.
e. NOTE: Care must be taken when rotating the 40x and 100x objective lenses into place. These lenses have a
spring retractable mechanism, which retracts slightly into its housing if the front of the lens, strikes the specimen
slide. With fine focus adjustment at mid-range, the rack stop has been adjusted at the factory to assure the 40x
and 100x lens will clear the thickness of a normal specimen slide and cover slip. However, if the rack stop has
been improperly adjusted, or if using a thicker than normal slide or cover slip, moving the 40x and 100x lenses too
quickly or carelessly could cause damage to the front lens element or to the slide.
f.
In order to obtain maximum resolution of the 100x oil immersion lens, it is necessary to apply immersion oil
between the cover glass of slide and front lens of the objective. Use a very small amount of immersion oil. All air
bubbles must be removed from between lens and slide by gently rotating nosepiece back and forth.
When you are finished viewing, all parts that come in contact with oil must be cleaned. Failure to do so could
permanently damage the 100x immersion objective lens.
Do not let the front lens element of the 40x objective lens come into contact with a wet slide surface, as prolonged
contact with any moisture could damage the lens. If lens is exposed to moisture, promptly wipe with soft tissue to
remove moisture.
