Abstract: A video camera system comprises a lens block and a camera block which are attachable and detachable through a block coupling mechanism to and from each other. The detachable lens block incorporates a focus lens drive mechanism for driving a focus lens and an autofocus control section for executing autofocus control. The autofocus control section receives a composite video signal obtained by processing a video signal from an image pickup device in a signal processing section of the camera block. The autofocus control section produces a focus control signal on the basis of the composite video signal to control the focus lens drive mechanism for the execution of the autofocus control. In addition, the detachable lens block is composed of an iris drive mechanism for optically adjusting an aperture of a lens and an autoiris control section for automatically controlling the iris drive mechanism, so that automatic iris control is executed on the basis of the composite video signal outputted from the camera block.