The Sigma AF 24-70 mm f/ 2.8 IF EX DG HSM is an all-purpose fast zoom lens for digital 35 mm and APS-C cameras of popular brands.
Equivalent focal length on APS-C cameras: 38-112 mm (depending on a crop-factor).
It has been designed to succeed the Sigma AF 24-70mm F2.8 EX DG MACRO and is gradually ousting the latter from the market. The engineers have done their best to remove shortcomings of the previous version, but the lens has become almost twice as expensive. Basic differences - ring-type HSM; system of internal focusing (IF); a bit heavier weight and smaller length.
It features the constant aperture of f/2.8 throughout the entire range of zooming.
At f/2.8 the image is soft, though a bit sharper than that of the previous version. From f/4.0 and especially from f/5.6 onwards the lens is rather sharp.
Rounded 9-blade aperture. Bokeh looks rather attractive for a zoom lens, though a bit coarse. Circles of confusion are almost ideally round.
The optical scheme includes three aspherical lenses (one molded and two hybrid) minimizing aberrations. Besides, there is one ELD and two SLD elements for correction of chromatic aberration in the optical scheme.
The Sigma AF 24-70 mm f/2.8 IF EX DG HSM takes advantage of the system of internal focusing (IF). The front lens does not rotate while focusing, which enables the use of a petal hood, polarized and gradient filters. It is possible to manually adjust sharpness at any time by turning the focusing ring.
Due to the built-in HSM the focusing is fast and silent. The problem of the autofocus hunting in this version of the lens has also been solved.
Color rendering is natural, colors are not saturated. Image contrast is high.
At wideangle sharpness is good in the frame center and on the edges. There are minimal drops in resolution on the edges.
Vignetting is minimal throughout the entire range of focal lengths and aperture values.
Barrel distortion is visible at 24 mm.
Owing to the improved multi-coating of the lens, side and back lighting is well handled, but the use of hood is recommended.
There are some macro abilities. At 70mm and a closest focus distance of 38 cm it is possible to take a 1:5.3 scale pictures.
The Sigma AF 24-70 mm F2.8 IF EX DG HSM is perfect for all types of photography, especially on 35 mm sensors. It is fit for genre and candid photography.
Compatible hood: LH876-01 571
A soft carrying case and a petal hood are included with the lens.
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Posted by: Sergei Borodin Date of publication: 13.09.2010