I just read this great piece on Luminous Landscape about how emotion can, does, and should affect every artist's work. Bill Neill describes how he fell into a 5' deep water hole with all of his camera gear at Zion National Park. The next day, he took a beautiful shot of water's effect on the desert floor, with the gear he was able to salvage.
(Click Here) to read his article on Luminous Landscape.
In my own experience, when emotion does affect me, it results in my most meaningful photographs. Of course, since I associate the emotion with the image, it is probably most meaningful to me. I have no real way of saying if that emotion translates to others.
In the shot above, I was driving around rural Maryland on my own, looking for something to photograph. I knew that my Grandma was quite ill, and it wouldn't last long. That said, we'd had a few false alarms already, so it was hard to tell just how serious it was. I heard later that night that she had passed on. This was Grandma's final sunset, even though she didn't get to see it. I literally caught it out of the corner of my eye, quickly pulled over, and shot it. It is not an ideal shot - a nice barn in the foreground would have helped. However, it was a vanishing instant, and was gone before I could relocate or recompose. For me, the shot has incredible meaning. I don't expect others to feel it. Actually, I'm quite happy experiencing that on my own.
This is why photography means something to me. I have no other way to communicate, or even remember the true feel of emotion at times like that.