Sigma AF 120-300mm f/2.8 APO EX HSM DG OS (Canon EOS) - Review / Lens Test
Lens Reviews - Canon EOS (Full Format)

Review by Klaus Schroiff, published May 2011


The Sigma AF 120-300mm f/2.8 APO EX HSM DG OS is a quite unique lens. It is the only full format zoom lens with a max. focal length of 300mm combined with a large aperture of f/2.8. Even more unusual is the pricing though - 300m f/2.8 prime lenses are extremely expensive often in excess of 5000EUR/6000US$. The Sigma costs "merely" half than that and is as such within reach of (some) normal mortals. It is also not much more expensive than the shorter Canon EF 70-200mm f/2.8 USM L IS II which represents the benchmark in the class of fast tele zoom lenses. Regarding its longer focal length the Sigma is more suitable for sports/action photography rather than portraits. Combined with the Sigma APO converters it can be extended to either a 168-420mm f/4 (1.4x) or a 240-600mm f/5.6 (2x).

The Sigma lens is a massive construction based on a rubber-coated metal body based on a metal mount. At roughly 3kg you better take some exercises in order of being prepared to carry such a lens all day long. Sigma added a sturdy tripod mount with a smart, grip-like design which also helps a bit here. Both the zoom as well as the focus control ring operate smoothly without any tendency of wobbling. The physical length of the lens remains constant regardless of the zoom and focus position. It features an internal focusing (IF) system resulting in a non-rotating front element.

The combination of IF and Sigma's HSM (Hypersonic motor) is also responsible for the very fast and virtual silent AF. We had no issues with AF accuracy on our EOS 5D II test body. The 120-300mm f/2.8 is actually the 2nd incarnation of the design but this latest version features a optical stabilizer (OS) which a claimed efficiency of about 4 f-stops which roughly matches our field experience. The OS features two modes - a conventional mode for static scenes and a "panning mode" for object tracking.

Optical construction 23 elements in 18 groups inc. 1x SLD+ 2xFLD elements
Number of aperture blades9 (circular)
min. focus distance1.50-2.50 m (max. magnification ratio 1:8.1 @ 200 mm)
Dimensions114 x 289 mm
Weight2950 g
Filter size105 mm (non-rotating)
Hoodbarrel-shaped, bayonet mount, supplied
Other featuresdetachable tripod mount, compatible to the Sigma AF 1.4x and 2x APO tele converters, Super Multi Layer (SML) coating

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