It boasts a fast maximum aperture of f/2 for selective focus effects and for working in low-light conditions. In order to ensure high-quality imaging in a range of conditions, the lens incorporates three aspherical elements, including one Advanced Aspherical, and two extra-low dispersion elements, all of which help minimize aberrations. For fast, responsive focusing the 28mm uses a linear motor and internal focus design. Also, it has a dust- and moisture-resistant construction that will permit operation in less-than-ideal weather conditions. Additionally, it has a nine-blade circular diaphragm for smooth bokeh. If you are looking for a wider perspective, the 28mm can accept optional ultra-wide and fisheye converters than will transform the lens into a 21mm or 16mm lens, respectively.