12
CX21
ONE-POINT ADVICE
How To Track a Microscopic Image
To track an image
moving leftwards
(or to move the
specimen image
rightwards):
Direction of moving the image
Total Magnification
The size of the specimen image for observation is obtained by multiplying the eyepiece magnification by the
objective magnification. This value is referred to as total magnification.
Example: Eyepiece (10X) x Objective (40X) = 400X
Resolution
Resolution determines how finely a lens is able to distinguish the details of a specimen.
The resolution of a microscope is mainly determined by the ability of the objective and is scarcely related to that of the
eyepieces. The only function of the eyepieces is to magnify an image already resolved by the objective.
Although both configurations above provide the same total magnification, the higher magnification of the objective
yields a better specimen resolution.
Field Number (FN)
The field number is the diameter of the image observed through an eyepiece, represented in millimeters.
10X eyepiece: 18 mm WHC15X: 12 mm
Actual Field of View
The actual field of view is the size on the specimen actually
observed in the microscope. This yields approximate size of
the actual specimen.
Actual field of view = Field number/Objective magnification
When the 10X eyepiece above and 10X objective are used,
the actual field of view is equal to:
Actual field of view = 18/10 = 1.8 mm
Move the slide
glass to the
left.
To move the
specimen image
upward:
Move the slide
glass down.
}The image observed through the microscope moves in
directions opposite to the actual up-down and left-right
movements of the specimen.
Actual field of
view: 1.8 mm
Approx. 0.9 mm,
about half of actual
field of view.
