21
CX33
5
Glossary of optical performance terminology
Total magnification
Field number
Resolution
The size of the specimen image to be observed is obtained by multiplying the eyepiece magnification by the objective
magnification. This value is referred to as the total magnification.
Example: Eyepiece (10X) x Objective (40X) = 400X
The resolution is the ability of the lens to separate the image created by multiple proximal points.
The resolution is mainly determined by the ability of the objective and scarcely related to that of the eyepieces.
The function of the eyepieces is to just magnify an image already resolved by the objective.
The field number is the diameter of the image viewed through eyepieces indicated in millimeters.
Even with the same magnification, the larger the field number is, the larger field of view can be observed at a time.
Standard 10X eyepiece: 20mm
WHSZ15 x -H: 16mm
Actual field of view
Field number
Actual field of view =
Magnification of objective
Example : If the field number of the eyepiece is 20 and the magnification of the objective is 10X,
Actual field of view = = 2.0 mm
The actual field of view is the size of the specimen actually viewed through eyepieces. This makes it possible to find out
the approximate size of the specimen.
20
10
Approx. 1.0 mm, about half of actual field
of view.
Actual field of view: 2.0 mm
