Let's consider water. It has an IOR of 1.3333. When pointing almost directly at an observer, and also almost directly at the sun, about 2% of the sun's light is reflected to the observer. And yet, a camera will show that spot as completely burned out - greater than the maximum it can show. Thus, in a photo, reflections of the sun, even when only at 2% of original intensity, are blown. This shows us that the sun is at least 50 times brighter (1 over .02) than the other objects being photographed.

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Renderosity forum reply notifications are wonky. If I read a follow-up in a thread, but I don't myself reply, then notifications no longer happen AT ALL on that thread. So if I seem to be ignoring a question, that's why. (Updated September 23, 2019)