Section 5 Operating Instructions
5-5
5.12 Focusing The Microscope
The coarse focus on the microscope system is achieved by raising or lowering the microscope assembly with
the spring arm. Fine focus is obtained by moving the ne focus objective lens.
The parfocal adjustment of the microscope allows the user to adjust the eyepieces to correct for
nearsightedness or farsightedness. It is essential to perform the parfocal adjustment prior to using any still or
video camera applications. If the parfocal adjustment is not performed, the microscope can still be focused on
a selected magnication, but other magnication settings may not be in focus.
The steps listed below should be followed for making the parfocal adjustments on the microscope:
1. Each operator of the microscope will require his or her own parfocal settings which should be
set before any procedures are performed. Due to changes in eye correction associated
with time, it is recommended that this procedure be performed by each operator a minimum of
one time per year.
2. Position the microscope above a at stationary surface, with the bottom of the objective lens parallel to the
surface.
3. Using a pen or pencil, mark an “X” on a piece of white paper for a focusing target and place it in
the center of the illumination eld of the microscope.
4. Depress the diopter tension lever and set the diopter adjustment rings on both eyepieces to “0”.
See Section 5.18 for additional information.
5. Without looking through the binoculars, adjust the ne focus objective lens to its approximate midpoint.
6. Set the magnication to the highest setting. Raise or lower the microscope vertically until the “X”
is in optimum focus.
7. Adjust the ne focus objective lens until a sharp focus is acquired.
8. Tighten the spring arm tension adjustment (See Figure 5-2 for location) on the spring arm assembly to
prevent the microscope from moving. Set the magnication to the lowest setting. Focus both
eyepieces, one at a time, by turning the diopter adjustment ring until the image is clear and sharp.
Use direct vision whenever possible to free hands for instruments.
NOTICE
It is particularly important to perform the parfocal procedure when an image through the
microscope is clear but the same image through a still or video camera is not focused, or
vice-versa.
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