Prime wide-angle lens is designed for full-frame Canon EOS DSLRs, and can also be used with APS-C-sized sensors where it will provide a 56mm equivalent focal length. The Blue Spectrum Refractive Optics element refracts shorter wavelengths of the visible spectrum (blue light) in order to significantly reduce chromatic aberrations and color fringing. A pair of aspherical elements and one UD element also help to control aberrations and distortions for sharper, clearer image quality. Subwavelength Coating minimizes surface reflections, ghosting, and flare for increased contrast and color fidelity. The Ultrasonic Motor offers fast and quiet autofocus performance and also permits full-time manual focus control by simply rotating the focusing ring. A minimum focus distance of 11″ with a 0.21x maximum magnification benefits working with close-up subjects. Fluorine coatings on the front and rear surfaces help reduce fingerprints and smudging. Featuring the L-series designation, this lens is also dust and moisture-resistant for use in trying conditions. A nine-blade aperture provides smooth and pleasing out-of-focus areas in selective focus images.