Magnification
Definition
In the microscopy context, it refers to the amount or degree of?visual enlargement?of an observed object.
Magnification is?measured by multiples, such as 2x, 4x and 10x, indicating that the object is enlarged to twice as big, four times as big or 10 times as big, respectively.
Concept
Simple magnifier lenses are?bi-convex. This means that it is thicker at the centre as compared to the periphery. When light passes through the biconvex lens, the parallel rays of the incident light will converge at the?focal point, as shown in the?figure?below.
Figure 1: Light through a biconvex lens [1]
If a biconvex lens is near an object?inside?its focal point, a?virtual?upright image?can be seen.?The lenses of the microscope’s eyepiece create a virtual image because your eye is within the focal point.?The eyepiece will only?enlarge?the image of the specimen.
Figure 2: ?Two thin convex lenses are used to form a compound microscope [2]
On the contrary, if the?objective?lens focuses on the specimen?outside?the focal point creating a?real image.?This image from the objective will?increases the detail?or?resolving power?of that specimen, leading to a new terminology called?Resolution.?This allows users to look into a microworld. Hence, the higher the objective lens the better the resolution.?(We will talk about it in the next post)
Do note that?the eyepiece?does not contribute anything to the image where it simply spreads out the details.?This is why it is also referred to as?empty magnification?and has less than 20 times magnification.
Magnification Limits
Typically, a standard light-based microscope has a?maximum magnification of up to 1,500x. Any magnification beyond this will cause the image to be excessively fuzzy as the wavelengths of light will limit the clarity of the image.
References