Whether taking photographs on the go or carefully composing a shot in a studio the Sigma 40mm F1.4 Art DG HSM Lens lives up to its design every time. This Sigma Art lens is made for Nikon FX format DSLRs. Its optical construction includes 16 elements in 12 groups. There are FLD and SLD elements in the optical design to correct chromatic and spherical aberrations. The lens is fitted with a Hyper Sonic Motor that controls unwanted noise to ensure a silent autofocus operation. Manual override can be done during autofocus for accurately focusing on subjects in the frame. The lens has a 9-blade electromagnetic diaphragm that produces rounded bokeh in the out-of-focus parts of the frame. With the maximum aperture of f1.4 you can use the lens in low light conditions to obtain bright results. The dust- and splash-proof construction of this Sigma prime lens supports working in harsh weather conditions. You can connect the lens to an optional Sigma USB dock for fine-tuning the focus parameters and giving firmware updates.