Sigma's rectilinear ultra-wide for APS-C — note this is not a fisheye despite some listings, but the 8-16mm DC HSM.
The Sigma 8-16mm f/4.5-5.6 DC HSM is an ultra-wide rectilinear zoom for APS-C DSLRs, released in 2010. Despite occasional mislabelling as a fisheye, it produces rectilinear (straight-line) images. At 8mm on APS-C, it provides a 12mm equivalent — one of the widest non-fisheye fields of view available on crop sensors, useful for dramatic architectural and landscape perspectives.
Optical performance is good for such an extreme focal length. Sharpness is respectable in the centre and acceptable in the corners when stopped down. Distortion is impressively well-controlled for an 8mm lens on APS-C — far less than a fisheye alternative. Chromatic aberration is noticeable at the edges but manageable. HSM motor provides fast, quiet autofocus.
Available in Canon EF-S, Nikon F, Sony A, and Pentax K mounts. The bulbous front element means no front filter thread. Weight is approximately 555 grams. Build quality is solid. No image stabilisation. The DC designation confirms APS-C only coverage — using on full frame would produce severe vignetting.
Available on the used market at reasonable prices. Check the front element carefully for scratches — the bulbous design is vulnerable. The impossibility of front filters is a limitation for landscape photographers wanting ND or polarisers. A unique lens offering extreme wide-angle coverage on APS-C — the Sigma 10-18mm f/2.8 Art is the modern equivalent.