An initial design containing the first- and third-order properties of the four-group video camera zoom system using lens modules and its real lens design are presented. The optimum initial design with focal length range of 6.1693 to 58.4065 mm is derived by assigning appropriate first-order quantities and third-order aberrations to each module along with the specific constraints required for optimization. By thirdorder aberration theory, a real lens for each group has been analytically designed to match the first-order quantities and third-order aberrations at a given conjugates, and then combined to establish an actual zoom system. The combination of the separately designed groups results in a system that satisfies the properties of the zoom system consisting of original lens modules. As a result, we obtain a zoom system useful in video zoom camera employing the rear focus method.