What is the highest magnification of a general optical microscope?

Microscope uses the magnifying imaging principle of convex lens to enlarge tiny objects that can't be distinguished by human eyes to the size that can be distinguished by human eyes. Its main purpose is to increase the opening angle of nearby tiny objects to the eyes (objects with large viewing angle image on the retina), and its magnification is expressed by angular magnification M. Since the opening angle of the same object to the eyes is related to the distance between the object and the eyes, the magnification of the image at a distance of 25 cm (apparent distance) from the eyes is generally specified as the magnification of the instrument.

When observing an object with a microscope, the viewing angle is usually very small, so the ratio of viewing angles can be replaced by the ratio of tangents. At present, the resolution limit of optical microscope is 0.2 micron, and efforts are being made to 0.02 micron. Magnification is the magnification of the objective lens multiplied by the magnification of the eyepiece. At present, the magnification of eyepiece is generally 10x, and some can reach 20X. The magnification of objective lens is generally 40x, and that of oil mirror is 100x. And then digitally amplify. Therefore, the maximum magnification of an optical microscope is usually 1000-2000 times, and the obtained image can be multiplied by the digital magnification.