In operating rooms, communication errors between the surgeons and assistants may be a source of inefficiency or error. In laparoscopic surgery, the endoscopic camera is an essential device, usually held by a human, and, why not, by a robotic assistant. In this paper, a novel four-DoF isotonic foot interface for controlling an endoscope positioner is proposed, featuring two rotational and two translational DoFs of the foot. To have an intuitive control paradigm with minimum confusion for the user, the foot movements match the positioner movements in direction. The Thales delta robot is chosen as the slave. The robot's design is modified to provide the necessary four DoFs. Initial tests confirm the functionality of the proposed master-slave endoscope positioner system.