This full-frame format, ultra-wide rectilinear lens is constructed with 18 elements in 11 groups, with 3 aspherical elements, 1 high refractive element and 3 extra-low dispersion elements along with multicoated glass that helps reduce flaring and ghosting. Minimum focusing distance is 0.26 meters, which affords dramatic depth of field effects at both the narrower openings (f/22 minimum aperture) and, taking advantage of the 9-bladed diaphragm, when wide open. This manual focus lens has an aluminium alloy housing and comes with a petal-shaped lens hood.