Sigma 20mm f/1.8 EX DF RF Aspherical Wide Angle Lens for Nikon SLR Cameras Best
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Sigma 20mm f/1.8 EX DF RF Aspherical Wide Angle Lens for Nikon SLR Cameras Feature
- Lens Construction: 13 Elements in 11 Groups Angle of View: 94.5 degrees Number of Diaphragm Blades:
Sigma 20mm f/1.8 EX DF RF Aspherical Wide Angle Lens for Nikon SLR Cameras Overview
Sigma 20mm f1.8 EX DG Aspherical RF is one of several EX Series lenses. It is the first 20mm Super wide-angle lens in the world with a large aperture of F1.8 and angle of view 94.5°. It has Macro focusing capability with a minimum focusing distance of 20cm/7.9inches (reproduction ratio 1:4). The iris diaphragm has 9 diaphragm blades to obtain beautiful out of focus image. It incorporates an aspherical lens element in the front as well as rear lens groups, to minimize distortion, spherical aberration and astigmatism. The lens has non-vignetting optical construction, in order to obtain adequate peripheral brightness with open aperture. This is especially desirable for digital cameras. The lens incorporates a rear focus system eliminating front lens rotation, thus allowing the use of a Perfect Hood and easy use of polarizing filters. The lens also incorporates dual-focus mechanism. It is easy to hold the lens, since the focusing ring does not rotate during auto-focus, yet it provides adequate focusing torque of the focusing ring during manual focusing of the lens. The lens materials used in this lens are lead and arsenic free ecological glass.Sigma 20mm f/1.8 EX DF RF Aspherical Wide Angle Lens for Nikon SLR Cameras Specifications
The Sigma 20mm super-wide-angle lens provides minimal light falloff and superior peripheral brightness, helping you take masterful landscape shots or large family portraits. The lens is equipped with a high-quality Dual-Focus (DF) mechanism. The DF system makes it easy to hold the lens, as the focusing ring doesn't rotate during autofocus. At the same time, however, the lens still provides adequate torque for manual focusing operations. By incorporating a rear focusing system, Sigma made the lens compatible with petal-type hoods, which offer superior light blocking effects. In addition, the lens offers a super multi coating that reduces the flare and ghosting that often occurs in digital cameras, along with nine diaphragm blades to help you obtain beautiful out-of-focus images in the foreground and background. Other features include a minimum focusing distance of 7.9 inches, a maximum magnification ratio of 1:4, aspherical lens elements in the front and rear lens groups to compensate for distortion and spherical aberration, and a 94.5-degree angle of view.Specifications
- Focal length: 20mm
- Maximum aperture: f/1.8
- Lens construction: 13 elements in 11 groups
- Angle of view: 94.5 degrees
- Number of diaphragm blades: 9
- Minimum aperture: f/22
- Minimum focusing distance: 7.9 inches
- Maximum magnification: 1:4
- Filter size: 82mm
- Mount: Nikon
- Dimensions: 3.5 inches in diameter and 3.5 inches long
- Weight: 18.3 ounces
- Warranty: 1 year
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*** Product Information and Prices Stored: Mar 06, 2012 03:21:25
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