Sigma 20mm f/1.8, this super-wide-angle lens is ensured minimal lightfall- 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.

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.

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.

Handling
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.

Specification

Lens Construction: 13 Elements in 11 Groups Angle of View: 94.5 degrees Number of Diaphragm Blades: 9 Blades Minimum Aperture: F22 Minimum Focusing Distance: 20cm/7.9 in. Maximum Magnification: 1:4 Filter Size: Diameter 82mm Dimensions: Diameter 88.6mm x Length 89.5mm 3.5 in. x 3.5 in. Weight: 520g/18.3 oz. Corresponding AF Mounts: Sigma Canon Nikon(D) Pentax Sony / Minolta(D)

Lens-Hood: LH875_02 included

The sigma 20mm is relatively small - considering the extreme brighness, I expected a much larger lens, instead the 20mm is not too big and it is quite light.

It is a little larger than the Canon 20 f/2.8 and smaller than the Canon 20mm f/1.4.   The built quality is good, but a little noisy with AF.

Average retail price is around $ 460.00 US dollars.