Fog can be a very tricky subject to capture while still maintaining good exposure on your main subject. This image nicely captures the light playing on a fallen leaf while still showing the mist on the water which adds to the feel of cooler fall weather. I would have liked to see a bit more cropping using the rule of thirds on this image to give the focal leaf a bit more strength. Cropping so that the leaf is in the bottom right of the image would also increase the feeling of motion in the direction the leaf is pointing.

