A light-to-digital converter (2) comprises a light-to-current converter (10); a current integrator (4) with an integrator output (30) resettable to a baseline level; and a counter (18) with a digital output (26), wherein the light-to-current converter (10) is switchably connectable as a positive integration input to the current integrator (4), for, during a light-collecting phase (404-406), integrating a current from the light-to-current converter (10), the integrator output (30) starting from the baseline value and ending at a value to be digitized; a reference current source (14) is switchably connectable as a negative integration input to the current integrator (4), for, during a counting phase (406-408) subsequent to the light-collecting phase (404-406), integrating a reference current from the reference current source (14), the integrator output (30) starting from the value to be digitized and ending at the baseline value, the time spent integrating the reference current corresponding to the value to be digitized; and the counter (18) is configured for measuring the time.