Sharath George Benny

Im sorry Zac, but I don't understand what you're trying to say here. You earlier said that luminaries don't necessarily follow inverse square law. I do understand the inverse square law, parabola and the parabolic reflector. But I don't see why luminaries don't necessarily follow inverse square law as you mentioned in your first comment. It'd be easier if you could say which light fixture in specific you have in your mind, that doesn't follow the law except for a laser?

Doesn't it? Except for the case of laser you mentioned, which is an exception. Luminaries does follow the inverse square law. Even for focused lights. If you check the the photometric data of a light fixture (like PAR), you'll notice that the light intensity in lux at any point multiplied by the square of the distance to that point from the light source will give you the total output of that source in lux.