Sigma 20mm f/1.8 EX DF RF Aspherical Wide Angle Lens for Nikon SLR Cameras
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.SpecificationsFocal length: 20mmMaximum aperture: f/1.8Lens construction: 13 elements in 11 groupsAngle of view: 94.5 degreesNumber of diaphragm blades: 9Minimum aperture: f/22Minimum focusing distance: 7.9 inchesMaximum magnification: 1:4Filter size: 82mmMount: NikonDimensions: 3.5 inches in diameter and 3.5 inches longWeight: 18.3 ouncesWarranty: 1 year