This Sigma 20mm F1.8 EX DG Aspherical RF Lens For Canon Mount  is an unique Sigma Lens offering with an aperture of F1.8 making it the fastest super wide angle lenses available from any camera or lens manufacturer.
For the scenic or landscape photographer it’s important to have a wide angle lens with excellent optical performance and Sigma’s aspherical lens technology provides high quality images for the serious shooter. Sigma’s 20mm lens has a field of view of 94.5º and yet provides for a close focusing lens-to-subject distance of only 2.6 inches. Such performance parameters provide great creative freedom to the photographer who wishes to exploit its capabilities for juxtaposing very near subject with the surrounding background. This extreme wide angle view also makes this lens ideal for crating “stitched” panoramic scenes for dramatic effect. The architectural photographer will find this lens attractive for shooting building interiors and the photojournalists will find its fast speed a life saver in low light conditions.
- Fastest wide angle prime available on the market
- Rear focusing system technology
- Carrying case, lens hood, front & rear caps
Wide angle lens with large aperture and superior peripheral brightness
This super-wide-angle lens is ensured minimal light-fall-off with superior peripheral brightness. The iris diaphragm has 9 diaphragm blades to obtain beautiful out of focus images in the foreground and background. This is an ideal DG lens optimized Digital SLR camera.
Minimum focus distance of 20cm (7.9 in.)
The minimum focusing distance of this lens is 20cm (7.9 inch) and it has maximum magnification of 1:4 with fast F 1.8 maximum aperture. The minimum focusing distance of 20cm (7.9 inch) and 94.5! angle of view allow close up photography surrounding the photographic subject.
The lens incorporates Dual-Focus (DF) 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 rear focus system eliminates the need for the front of the lens to rotate, thus allowing the use of a "Petal-type hood", which is superior light blocking effect.
Incorporated aspherical lenses
The use of aspherical lens elements in both of the front and rear lens groups effectively compensates for distortion, spherical aberration and astigmatism.