Sigma 20mm f 1.8 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 & angle of view 94.5 degree. 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 & 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 & 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 & arsenic free ecological glass. ...

Sigmas splash-proof feature is also included preventing dust & precipitation from getting inside the lens. One SLD & two FLD glass elements provides maximum correction of chromatic aberrations. The super multi-layer coating reduces flare & ghosting, & the lens design incorporates an inner focusing & inner zooming system to ensure sharp images throughout the entire zoom range. enhanced optical performance provides excellent correction of sagittal coma flare & ensures ultra-high resolution, comparable to a fixed focal length lens. The HSM (Hyper Sonic Motor) ensures quiet & high speed AF, while allowing full-time manual focus override. A truly unique product which is a rarity in the photo industry, this lens is the only lens of its kind on the market; a professional zoom lens that also features a fast aperture. Most professionals own the standard 300mm 2.8, but they also have to carry a shorter zoom lens for those times when the subjects move closer. That means fumbling around switching lenses or carrying a second camera body. The amazing Sigma zoom lens let you instantly determine the picture composition you want without having to change your vantage point. Imagine photographing courtside at a college basketball game & having the versatility to zoom in on a players face or hand & then instantly zoom back to capture the entire player making his shot. ...

To achieve an F2.8 aperture at all focal lengths, it employs three aspherical lens to provide optimum aberration compensation. Two Special Low Dispersion (SLD) glass elements are provided for color aberration compensation, to assure high image quality. ...

Sigmas EX DG filters benefit from multi-layer lens coating, developed to counteract the highly reflective characteristic of image sensors. With older style filters, light would reflect off the image sensor, bounce off the lens & filter elements & re-enter the image sensor, creating a ghost image. In addition to this, an optimum, neutral color balance is ensured, increasing the white balance accuracy of the digital camera. ...

This UV filter also perfectly eliminates the harmful effect of ultraviolet light. The multi-coated UV filter can be used with both color & black-&-white film & digital sensors. This is the most suitable filter for protective use & general photography. ...

This UV filter also perfectly eliminates the harmful effect of ultraviolet light. The multi-coated UV filter can be used with both color & black-&-white film & digital sensors. This is the most suitable filter for protective use & general photography. ...

This UV filter also perfectly eliminates the harmful effect of ultraviolet light. The multi-coated UV filter can be used with both color & black-&-white film & digital sensors. This is the most suitable filter for protective use & general photography. ...

This UV filter also perfectly eliminates the harmful effect of ultraviolet light. The multi-coated UV filter can be used with both color & black-&-white film & digital sensors. This is the most suitable filter for protective use & general photography. ...

Sigma is pleased to announce the launch of the SIGMA EX DG range of filters which is optimized for digital SLRs. These filters benefit from a super multi-layer lens coating developed to counteract the highly reflective characteristics of digital image sensors reducing both flare & ghosting. Black rimmed glass eliminates unnecessary internal reflections. ...

This UV filter also perfectly eliminates the harmful effect of ultraviolet light. The multi-coated UV filter can be used with both color & black-&-white film & digital sensors. This is the most suitable filter for protective use & general photography. ...