|Introduction | Sigma 17-70mm f2.8-4 lens performance | Sigma 17-70mm f2.8-4 versus competition | Conclusion|
For many people an introduction to photography is through a compact camera: usually, these days, one with a zoom lens covering medium-wide through to short telephoto. The next step is often an SLR and the “standard” zoom, covering the same range. The quality of this “standard” zoom can be the difference between great results and disappointment, so the choice is important. This Sigma 17-70 f2.8-70 f2.8-4 DC Macro OS HSM C Canon is both good and versatile, no disappointment here.
The Sigma 17-70 f2.8-4 DC Macro OS HSM C Canon is a “standard” zoom lens for APS-C cameras, in this case Canon. It is also available for Nikon and Sigma APS-C bodies. It covers the range 17mm to 70mm, the relative focal length for full frame 35mm would be 27.2mm to 112mm. This type of lens is aimed at photographers looking for a single, all purpose lens that will at the same time be compact enough to carry around. This particular lens is also equipped with a Macro setting allowing focussing down to 22cm giving a reproduction ratio of 1:2.9.
The design is of 16 elements in 14 groups, two of the elements are FLD (with characteristics similar to flourite glass) and one is SLD (Special Low Dispersion glass). It is optimised for use with digital capture, as one would expect for an APS-C lens and is equipped with optical stabilisation (OS), a hyper-sonic motor (HSM) for autofocus and a 7 bladed iris giving a round aperture. The diameter is 79mm, the length 82mm and the weight is 470g Sigma has recently introduced categories for its lenses, A for Art lenses, S for Sport lenses and C for Contemporary lenses.
This 17-70 is the first offering in the Contemporary category, the design characteristics of which are ‘Superior optical performance and compactness”. The construction of the lens includes “Thermally Stable Composite” (TSC) material for increased durability and reduction in weight. Sigma does not explain exactly what this material is but it has the benefits of polycarbonate components, but avoids their thermal expansion.