The Sigma 40mm F1.4 Art DG HSM Lens lets you achieve the quality of cine lenses with your full-frame DSLR. Designed for Canon EF-mount cameras, the lens construction uses 16 optical elements that are arranged in 12 groups. Three each FLD and SLD elements are included in the optical arrangement for reducing chromatic and spherical aberrations. This Sigma Art lens is compatible with Canon Lens Aberration Correction for correcting distortions further. The Hyper Sonic Motor AF keeps the operation noise low while accurately focusing on the object down to 15.7 inches. You can manually override the autofocus parameters to attaining critical focus. The 9-blade electromagnetic diaphragm creates smooth bokeh quality to enhance the shallow depth of field resulted by the maximum aperture of f/1.4. As the lens is resistant to dust and water splashes, you can use it inclement weather without any worries.