Microscope magnification and effective magnification
Due to the two magnifications of the objective lens and the eyepiece, the total magnification Γ of the microscope should be the product of the objective lens magnification β and the eyepiece magnification Γ1:
Γ=βΓ1
Obviously, compared with the magnifying glass, the microscope can have a much higher magnification, and the magnification of the microscope can be easily changed by exchanging the objective lens and eyepiece with different magnifications.
Magnification is also an important parameter of the microscope, but one cannot blindly believe that the higher the magnification, the better. The limit of microscope magnification is the effective magnification.
Resolution and magnification are two different but related concepts. Relational formula: 500NA<Γ<1000NA
When the numerical aperture of the selected objective lens is not large enough, that is, the resolution is not high enough, the microscope cannot distinguish the fine structure of the object. At this time, even if the magnification is excessively increased, the obtained image can only be an image with a large outline but unclear details. , called the invalid magnification. Conversely, if the resolution meets the requirements but the magnification is insufficient, the microscope has the ability to resolve, but the image is still too small to be clearly seen by human eyes. Therefore, in order to give full play to the resolving power of the microscope, the numerical aperture should be reasonably matched with the total magnification of the microscope.
