Distance sensor

The device (99) has a receiving unit for converting a reception radiation (12) into an electrical reception signal. An analog-digital converter (3) digitizes the reception signal, and an electronic evaluation unit (4) is designed such that a maximum distance (13) from a target object (11) is ascertained based on a signal propagation time using the digitized signal. A driver stage (5) is designed such that pulse durations of different length for optical pulses are set, where extension of one of the durations allows expansion of a distance measurement range as the ascertainable distance. The target is designed as a vehicle or a distant building. Independent claims are also included for the following: (1) an observation apparatus (2) a distance measuring method (3) a method for flexibly matching a distance resolution capability of an optoelectronic distance measuring device (4) a computer program product comprising a set of instructions for executing a distance measuring method.