A micro-explosion occurring after pulsed laser-induced breakdown in water can be effectively described as an optodynamic phenomenon. It is a source of shockwaves that propagate into the surrounding medium. We present a measurement of the source size based on far field detection of the propagatingwaves using a beam deflection probe technique. By taking into consideration the moving breakdown model the relation between the size of the breakdown region and the apparent size of the optodynamic source is shown. An energy dependent enlargement parameter d is introduced which describes the relation.