The inspection of semiconductors or like substrates by the present mechanism minimizes deflection in the checkplate and probe card. An inspection device including a housing, a toggle assembly within the housing, an objective lens assembly attached within the toggle assembly including an objective coupled within an objective focus, wherein the objective focus is deflectable along an optics axis, and a cam assembly including a rotary cam and a window carrier, wherein the window carrier is moveable along the optics axis with rotation of the rotary cam, wherein the cam assembly is coupled to the toggle assembly with the objective and window are aligned along the optics axis.