Sigma 50mm F1.4 CL DG: Smaller Than the F2, Full Metal, Weathersealed

Sigma has announced development of a 50mm F1.4 CL DG DN, a new I-series lens that comes in at 64.7x56mm and 375g: smaller than the existing I-series 50mm F2 DG DN despite the wider aperture. The design uses a new Rotary Direct Drive motor and whole-lens focusing rather than internal focus. 8 elements in 6 groups, three aspherical elements, one FLD element, full metal barrel, weathersealed.