Well I just picked up a 50mm 1.4 lens earlier this week. As I was playing with it I ended up taking a few shots out of my car window pointed at the mirror. I shot a series at f stops, 1.4, 2.0, 2.8, 4, 8, and 16. I thought how the DOF and bokeh interacted were really interesting. I also noticed how sharp the background was at all f stops.