A focus correction setting application is connected to an imaging apparatus such that the focus correction setting application can communicate with the imaging apparatus. The focus correction setting application holds, in a focus position correction amount table with respect to various light sources, focus position correction amounts for correcting a shift in a focus position caused by inserting or removing an optical filter into or from an optical path of a lens group of the imaging apparatus, selects a light source in a window, acquires a focus position correction amount corresponding to the selected light source among the held focus position correction amounts, and controls the imaging apparatus to correct the focus position by the acquired focus position correction amount when inserting or removing the optical filter.