The reduction of every single millimetre in focal length makes a noticeable difference in wide-angle coverage. The Sigma 8-16mm f/4.5-5.6 DC HSM lens shaves 2mm off the shortest zoom length of competing zoom lenses, boosting the viewing angle from around 108 degrees to a monstrous 121 degrees (measured on the diagonal). The difference is obvious and eye-popping as you look through the viewfinder.
While short in focal length, the Sigma isn’t short in build, and is a third longer than Canon’s 10-18mm lens. It’s twice as heavy as well, but the construction feels solid and sturdy. There are no weather-seals but the mounting plate is metal, not plastic. A conventional ring-type ultrasonic system delivers fast and quiet autofocus complete with full-time mechanical override, and a focus distance scale.
In terms of optics, the lens contains four top-quality FLD (Fluorite-grade Low Dispersion) elements and Sigma’s usual Super Multi-Layer Coatings to guard against ghosting and flare. As with most full-frame compatible lenses of comparable focal length, the lens hood is built-in to protect the bulbous front element, so there’s no attachment thread for filters. However, one thing to note is that the two-part cap enables 72mm filters to be used at long zoom lengths.
Even when using the widest available aperture at the shortest end of the zoom range, sharpness remains impressive across the entire image frame, which is no mean feat considering the ultra-wide viewing angle. Colour fringing and distortions are well controlled, making this lens the ideal choice if you want to maximize your viewing angle without compromising on the quality of your images.
The 8-16mm f/4.5-5.6 DC HSM handles nicely, with its focus ring mounted towards the front and a focus distance scale nested between the focus and zoom rings. The attention to detail and quality on the inside and out of the lens is reassuring, especially given how extreme the viewing angle is. It could have been a novelty gimmick lens, but Sigma took the time and effort to ensure this is a premium optic for producing memorable images of faultless quality.