The Field of View (FoV) is the diameter of the circle of light that you see when looking into a microscope. The higher your magnification, the smaller the microscope field of view will be.
The benefits a microscope objective
The imaging system of the Nexview 3D is a microscope objective, which gives the two-fold benefit of:
In optics, the numerical aperture(NA) characterizes the range of angles over which the system can accept or emit light. When the light hits a surface which is highly sloped, it can be reflected to not return up the optical system, and nothing will be detected. This means that higher NA objectives can measure steeper slopes.