Designed as a DX workhorse, the Nikon AF-S DX Zoom-NIKKOR 17-55mm f/2.8G IF-ED is a 25.5-82.5mm-equivalent zoom characterized by its bright maximum aperture and sophisticated optical design. The fast f/2.8 constant maximum aperture benefits working in difficult lighting conditions and also enables greater control over depth of field when working with selective focus techniques. The optical design incorporates three aspherical elements and three extra-low dispersion elements, which help to greatly reduce spherical and chromatic aberrations throughout the zoom range.