Magnification of microscope

The magnification of a microscope is determined by the length of eyepiece, objective lens and lens tube.

For commonly used microscopes with a tube length of 160 mm, the magnification is directly engraved on the eyepiece. For example, 5 × means 5 times magnification; 10 × means 10 times magnification. It can be replaced if necessary. An eyepiece with a larger magnification has a shorter lens, which is called a high magnification eyepiece.

The objective lens is also engraved with the magnification, and also marked with the main performance parameters of the objective. For example, 10 / 0.25 and 160 / 0.17 are marked on the 10x objective, where 10 is the magnification, 0.25 is the Na value, 160 is the barrel length (in mm), and 0.17 is the required cover glass thickness (in mm). 10 times objective is called low power objective, 20 times objective is called medium power objective, 40-65 times objective is called high power objective, 90-100 times objective is oil lens.

The final magnification of the object is the product of the magnification factor engraved on the eyepiece and the objective lens. Theoretically, the maximum magnification of the microscope can be up to 2250 times. However, due to the limitation of resolution and technology, the maximum effective magnification of the best microscope can only reach about 1400 times. Sometimes it is said that a microscope can be magnified by 2000 times, which is only able to magnify 2000 times. The clarity is not necessarily high, or it may just see an enlarged fuzzy image.

The objective lens is mounted on the hole of the converter and consists of a set of lenses, which can clearly enlarge the object.

An eyepiece is a lens inserted at the top of the barrel and consists of a set of lenses. It can further enlarge the real image magnified by the objective lens, which is equivalent to a magnifying glass.