Canon 100-400 mm lens, and didn't have anything shorter. So, I started playing with the fog depth, where the fog would change how it affects the image as you get further away. In this particular case, the fog also changed thickness even from left to right. It was moving slowly in bunches, causing some interesting patterns.
I chose to use the image stabilization, even though I was only shooting at 100mm 1/320 second. Should have brought the tripod along, but oh well.
What I found interesting was the patterns in the fog, combined with the reddish tree against the green. I could have increased the saturation to bring out some of the colors, but that would have decreased the affect of the fog on the scene. It's certainly interesting to try and balance out the muting of the fog with the color in the landscape.
This was take at North Lake, Golden Gate Park.