Your night vision is extraordinarily good, even for a vampire. The deepest shadows are like looking into a well-lit room for you. However, in normal light or bright conditions, you have to switch back to less-sensitive vision, or the weakest light quickly blinds you. While your night sight is active, you suffer no penalties for the dark and can see perfectly well. Should you use it in well-lit conditions; you suffer a penalty inversely proportional to the usual penalties for darkness.