Girl in a crowd, 1/250, f5.6, 310mm, ISO400.
As the next photo needed a wide depth of field to cover foreground to infinity I chose a wide angle lens and an aperture which was a reasonable compromise from the available light and the necessary aperture setting. An aperture of f11 with a focal length of 17mm gave me all that I needed to keep the entire picture sharp.
Chicago in water, 1/125, f11, 17mm, ISO400.
1. The depth of field change that occurs when moving from a wide angle to a long telephoto lens is due to the reduction of viewing angle that a long lens produces. If the same subject is photographed with differing lenses and is kept the same size by moving closer as the focal length reduces, then the depth of field remains constant. This concept is now fairly well accepted, certainly by me.