An electro-optical device includes at least one laser light source and a beam steering device, which transmits and scan the at least one beam across a target scene. One or more sensing elements output a signal indicative of a time of incidence of a single photon on the sensing element from the target scene. Circuitry processes the signal in order to determine respective distances to points in the scene and controls the light source to emit the beam at the low level during a first scan, to identify, based on the first scan, the points in the scene that are located at respective distances from the device that are greater than a predefined threshold distance, and to control the laser light source during a second scan to emit the beam at the high level while the beam steering device directs the beam toward the identified points.