Sigma has for the first time marketed a true fisheye optic for crop sensors, projecting a circular 180° image onto APS-C sensors. The new lens sports a focal length of 4.5mm and maximum aperture of f/2.8, HSM silent focusing and SLD low-dispersion lens elements. Aside from the 'edgy' skateboarding shots and frankly unflattering portraits often seen, circular fisheyes are actually quite useful for astrophotography and scientific applications. Pricing and availability is yet to be announced.
