introduced in 2012, this is a superb lens from Sigma which is optically superior to the Canon, Nikon, Sony or Carl Zeiss 35mm lenses although it is not weathersealed and bokeh is not as nice as it could be
specs
35mm full frame lens in Canon, Nikon, Pentax, Sigma or Sony mounts
13 elements in 11 groups with 4 SLD, 1 FLD and 2 aspherical elements
9 rounded blades
closest focus 0.3m giving 0.19x magnification
ring type HSM focus motor with full time manual control
superb optics that beat anything else in its class, reasonably sharp in the centre wide open, very sharp at f/2.8 but requires f/5.6 for highest levels of sharpness across the frame
impressive flare resistance
fast, silent, and accurate autofocus
excellent build quality
slightly fussy rendition of out-of-focus backgrounds under some conditions - ie. bokeh may not be as nice as one would like
some vignetting up to 2EV in the corners at f/1.4, 1 EV at f/2.0 and 0.5EV at f/2.8
minimal barrel distortion of 0.8% on the long edge and 0.24% on the short edge