While Sigma’s lighter, much cheaper and slightly wider 35mm f/1.4 DG HSM | Art lens is perhaps a more sensible option for many, the 40mm f/1.4 DG HSM | Art lens's sterling optical performance deserves high praise.
Excellent sharpness, even wide open, Great corner sharpness at f/1.4, Lovely out-of-focus areas, Solid build quality, Virtually non-existent chromatic aberration
Noticeable vignetting at widest apertures, AF sounds picked up on video, Very large for a 40mm lens, Far pricier than other logical alternatives, Heavy