A lighting system comprising a lamp arranged to transform electricity into a light beam having properties such as intensity, colour, colour temperature, direction and beam cone angle; a light control means arranged to adjust said light beam properties; an ultrasonic transmitter arranged to transmit ultrasonic signals; an ultrasonic receiver arranged to receive reflected ultrasonic signals; and a processing means arranged to derive a time-of-flight signal representing the time differences between said transmitted and received ultrasonic signals and to send control signals to said light control means in dependence of said time-of-flight signal, wherein said processing means and said light control means are further arranged to change from adjustment of one of said light beam properties to adjustment of another one of said light beam properties, if a predetermined behaviour in said time-of-flight signal is determined.