focal depth of microscope
The depth of focus is the abbreviation of the depth of focus, that is, 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 within a certain thickness above and below the plane. Clearly, the thickness of this clear part is the depth of focus. When the depth of focus is large, the whole layer of the object to be inspected can be seen, while the depth of focus is small, only a thin layer of the object to be inspected can be seen. The depth of focus has the following relationship with other technical parameters:
(1) The depth of focus is inversely proportional to the total magnification and the numerical aperture of the objective.
(2) The depth of focus is large and the resolution is reduced.
Due to the large depth of field of the low magnification objective lens, it is difficult to take pictures with the low magnification objective lens.
