A vehicle rearview mirror system includes a rearview mirror assembly comprising an electro-optic reflective element and, preferably, at least a first and a second photo-sensor, both facing generally in a common direction. The system further includes a light piping element that pipes light to the first photo-sensor from a light environment different from the light environment to which the second photo-sensor is exposed. The first photo-sensor comprises a semiconductor photo-sensor sensitive both ...