The invention relates to a variable transmittance device including at least one variable transmittance lens and a control circuit comprising at least one sensor suitable for measuring an illuminance (E), the control circuit being suitable for automatically controlling the value of the transmittance of the variable transmittance lens depending on the illuminance (E) measured by the sensor, wherein the control circuit defines a plurality of successive illuminance ranges (P) each illuminance range (P) being bounded by a minimum illuminance value (Emin) and a maximum illuminance value (Emax), and wherein the control circuit is suitable for controlling the transmittance of the lens to a plurality of setpoint transmittance values (Tv) respectively corresponding to said plurality of illuminance ranges (P).