My girlfriend and I, along with another couple, were overjoyed just to have gotten permits to hike in and camp at Havasupai, but when we got down to the water to relax after the ten mile hike in, we were treated to this view almost immediately - a clearing storm created once-in-a-lifetime conditions that had me scrambling to get my gear out and ready to rock before the rainbow disappeared. I was almost shaking with excitement as I screwed on a 3-stop neutral density filter and then dropped in a 3-stop graduated neutral density filter to the front of my Canon EF 16-35mm f/2.8L, which was connected to my trusty Canon 6D. Once the camera was mounted up to my tripod, I set my ISO to 100 and then engaged live view so that I could get as close to a decent exposure by eyeballing it as possible in the shortest amount of time as I knew the rainbow was likely going to be fleeting (it was, 1-2 minutes max). Using live view as a visual guide, I stopped down to f/11, selected a shutter speed of 0.8, adjusted the grad and then let it rip. As you could imagine, I was over-the-moon excited when I saw the preview of this shot come up on the back of the camera after the exposure finished!