Murray, I have had this kind of experience a few -very few- times.

I had a similar experience to your "Red Cedar" when I saw Manuel Alvarez Bravo's "Portrait of the Eternal" http://masters-of-photography.com/A/...rnal_full.html
in the MOMA a few years ago. The entire retrospective exhibition was excellent, but when I came to this photo I was absolutely transfixed. I stood and stared at it for at least 15 minutes before I could move on. I saw the rest of the show, then returned to this photo and stared for another 15 minutes or so. Then we left the exhibition to view the rest of the museum. We were about to leave when I stopped and told my wife, "I have to see it one more time!" and I returned to the Alvarez Bravo exhibit for one last look at this photo. It still takes my breath away every time I see it, even if it is only on a computer screen.

Another experience was while shooting. My specialty is dance and theater photography, and I see a lot of good ballet and modern dance. Once I went to a small performance of modern dance by my friend Paulette. When I arrived, she introduced me to Arleen, a petite young woman who was going to sing that night during one of the numbers. Fine, how do you do, nice to meet you, etc.
When the number came up, Paulette was dancing while Arleen stood in the background. The music was an aria from "Aires Brasileņas" by Hector Villalobos. I shot Paulette for a minute, but then I was overcome with the music. I actually lowered my camera -something I had never, ever done during a performance- and looked around to see where this heavenly sound was coming from. I assumed it must be a recording, but I had seen no sound equipment. Then it hit me: it was coming from Arleen, the tiny young woman I had met before the show!! The sound was so powerful, so overwhelming, that I could not believe it could come from her small body. I was moved to tears, and it was very difficult to resume shooting. After the performance I had to find Arleen; but I could not find words to express how powerful was the experience she had given me.

--Eddy