Adorama has the well-regarded SIGMA 28mm f/1.4 DG HSM Art for the lowest price that we have ever seen at only $449.
Both Canon and Nikon mounts are $449, while the Sony E mount version is $539.
This really is a steal of a deal.
SIGMA 28mm f/1.4 DG HSM Art Key Features
Dust- and splash-proof structure
Designed to minimize flare and ghosting
Designed to meet all shooting conditions
Manual Override (MO) capable of switching two full-time manual modes
Fixed Focal Length: 28mm Lens
Maximum Aperture: f/1.4
Image Stabilization Type: No
SIGMA 28mm f/1.4 DG HSM Art $449 at Adorama