This fall-colored leaf is covered in hoar frost. The frost creates a sharp contrast with the dark red leaf and the very dark background.
An f/2.8 aperture yields a very thin DOF at this short focus distance. Careful alignment of the leaf is necessary to keep an adequate portion of the subject in focus. The benefits of the narrow aperture are a faster shutter speed (it was extremely windy at the time of this shot) and a completely-blurred background.
This shot was taken handheld at 1/25 and near 1:1 / 1x magnification thanks to IS.