What is the depth of focus of a microscope?

The depth of focus, that is, the depth of field of the microscope, is the abbreviation of the depth of focus.

Usually when using a microscope, when the focus is on an object, not only the points on the plane of the point can be seen clearly, but also the points within a certain thickness above and below the plane can be seen clearly, then this The thickness of the clear part is the so-called depth of focus, that is, the depth of field of the microscope.

Generally speaking, when the focal depth is large, the full layer of the inspected object can be easily observed, such as our reseach level stereo microscope has good depth of focus.  while when the focal depth is small, only a thin layer of the inspected object can be seen. 

At the same time, the depth of focus is related to other technical parameters as follows:
1. The depth of focus (that is, the depth of field of the microscope) is inversely proportional to the total magnification and the numerical aperture of the objective lens;
2. The greater the depth of focus (that is, the depth of field of the microscope), the lower the resolution, and because the depth of field of the low-power objective lens is large, it may cause difficulties when using a low-power objective lens for photomicrography.