A zoom lens system of a color television camera is divided into a front lens component comprising a zooming lens system and a front part of a relay lens system, and three equivalent rear lens components each comprising a rear part of the relay lens system. A color separating prism system is located between the front and the rear parts of the relay lens system. The rear lens components are convergent so that the angle of light beams incident into the prism system may be smaller than that of the light beam incident into the image pick-up tubes.