Additional information:
The Sigma 18-250 mm f/ 3.5-6.3 DC OS HSM is a compact all-purpose 13.8x superzoom with a built-in optical stabilizer for digital APS-C cameras of main brands.
It is positioned as an all-purpose lens for travel photography and a kit lens for everyday use. It will suit beginning photographers as a perfect device for determining his/her own preferred focal lengths.
Equivalent focal length: 27-375 mm. At a maximum focal length of 250 mm the lens extends and becomes twice as long.
In 2009 the lens was given a prestigious international award by the Technical Image Press Association.
The lens is equipped with a 4-stop optical stabilizer which enables shooting in insufficient lighting and more effective use of maximum zoom lengths especially when shooting handheld.
Designed by Sigma, the system of optical stabilization uses two sensors which detect camera movings in the vertical and horizontal planes. The stabilizer is effective for shooting moving subjects. As the stabilizer is built into the lens, it prevents not only photograph blurring, but also image blurring in the viewfinder and on the camera LCD screen, which makes cropping more convenient.
Sony and Pentax modifications are also equipped with optical stabilizers. But using them, a photographer has to choose: either to use an optical stabilizer or a built-in sensor-shift image stabilization.
The optical scheme of the lens includes four SLD elements and three aspherical lenses. Aberrations are well corrected, but there is visible distortion (barrel distortion at wideangle and pincushion distortion at longer focal lengths) and chromatic aberration when shooting contrast scenes.
The Sigma 18-250 mm f/3.5-6.3 DC OS HSM uses the system of internal focusing. The front lens does not rotate while focusing, which enables the use of a petal hood, polarized and gradient filters.
Due to the built-in HSM, the focusing is fast and silent. There is focus hunting occurring at a maximum focal length.
Color rendering is natural, colors are not saturated. Contrast is average.
At wideangle sharpness is good in the frame center and on the edges. At full talefocus sharpness is average; there is a considerable drop in resolution on the edges of the frame.
Due to the multi-coating, side and back light is well handled by the lens, but it is better to use the hood.
There are macro facilities. At 200mm and a closest focus distance of 45 cm it is possible to take a 1:3.4 scale pictures.
The Sigma 18-250mm f/3.5-6.3 DC OS HSM is fit for all major types of photography. This is an ideal travel lens.
Compatible hood: LH780-04 581
Soft carrying case and petal hood are included with the lens.
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Posted by: Sergei Borodin Date of publication: 13.09.2010
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