A method and circuit arrangement dynamically calibrate a photosensitive control for a light source that includes a voltage divider circuit coupled to a resistive light detector and configured to output to a comparison circuit a variable voltage signal that varies with the resistance of the resistive light detector. To calibrate the photosensitive control, a variable impedance circuit in the voltage divider circuit is adjusted to null out any changes in voltage caused by feedback from the controlled light source. The amount of correction is proportional to the amount of light feedback. Based on the amount of correction needed, a new reference voltage is selected that will accurately detect the next dusk to dawn transition while the light feedback is present.