I'm known as being a feather collector - can't resist photographing them too. Trying to get detail in a feather floating by the bridge, such a small feather, I decided to try spot metering to see what effect I could get. It was quite hard to keep the focus on such a small thing on a moving surface and I had several failures, but I kept trying and this is one of the successes. What I liked is how the river water darkened and displayed the white feather perfectly. I used Aperture Priority which stopped at 6.5 when I zoomed in fully, and the spot metering faded out the surrounding water beautifully. You can also see the surface tension on the water around the feather.