24 PART I Basics of Microscopy
Term Description
Magnification The purpose of magnification is to ensure that a detail is displayed
large enough for the human eye to see it.
Resolution The purpose of resolution is to make it possible to differentiate
specific details from neighboring details.
Contrast The purpose of contrast is to ensure that a detail exhibits a significant
difference in brightness or color to its surrounding environment.
Sharpness Sharpness is best described as the line contrast of resolved structures.
Depth of field This is the thickness of the optical section of an object through which
a sharp image is observed through the entire stack.
Table 2.1: Important physical terms
The Microscopic Magnification
To be recognized, details must be displayed at a sufficient size. In other words,
magnification is the ability to make small objects seem larger, such as making a
microscopic organism visible to the human eye. A microscope’s total magnification
is a combination of the eyepieces and the objective lens.
The objective magnification ranges from low to medium to high and is indicated
on each objective lens.
Object
magnification
Good for Challenge
Low 1× to 5× Large overview
images for samples
sizes up to 25 mm
It can be difficult to illuminate large
object fields homogenously
Medium 10× to 40× Suitable for most
applications
Incorrect color reproduction,
spherical aberration due to incorrect
sample conditions may occur
High 60× to 100× Small samples and
fine structures
Stray light reduces the contrast in
finely structured details; insufficient
resolution, color reproduction,
spherical aberration, image
brightness may occur
Table 2.2: Low, medium and high magnifiction
By simple multiplication with the magnification of the eyepieces you get the total
magnification performance of your microscope.
20 objective 10 eyepiece 200 total visual microscope
magnification