The invention relates to a photoplethysmography (PPG) apparatus (100), comprising at least one light source (110) configured to generate a beam of source light (114) having a source beam angle (118) and at least one controllable beam angle adapter (120) configured to receive a beam-angle control signal (170) indicative of a modified beam angle (124) to be set, the beam angle adapter (120) being further configured to provide the beam of source light (114) with a modified beam angle (124) to an external object (130). The PPG apparatus (100) comprises at least one PPG sensor(140)configured to provide a sensor signal (145) indicative of source light (150) scattered by the external object (130), and a PPG evaluation and control unit (160) configured to receive the sensor signal (145), to provide the beam-angle control signal (170) and to provide at its output (180) an AC signal component of the sensor signal (145).