The Sigma AF 20 mm f/ 1.8 EX DG ASPHERICAL RF is a wide-angle lens for modern film and digital Sigma cameras.
It is the fastest 20mm lens on today's market.
With a lens speed of 1.8, it enables shooting in poor lighting conditions without a tripod or flash.
Two aspherical elements in the optical scheme effectively combat distortion, chromatic aberration and astigmatism.
The Sigma AF 20mm f/1.8 EX DG ASPHERICAL RF blurs at f/1.8 especially when the subject is more than 3m away. Yet, the results are quite acceptable. The situation remains the same up to f/2.2. From f/2.2 it is sharp. And it is very sharp from f/4 onwards.
Vignetting is visible up to f/2.2, it is not manifested farther.
There are insignificant drops in resolution on the edges.
Focusing is internal. Manual focusing can be switched on at any time by turning the focusing ring. The front lens does not rotate during focus operations, which enables the use of special caps, petal hood, as well as gradient and polarized filters.
The pictures taken with this lens have beautiful coloring and good contrast. The lens is quite well resistant to back and side lighting, especially with a hood.
The Sigma AF 20 mm f/1.8 EX DG ASPHERICAL RF is perfect for shooting landscapes, architecture, interiors, as well as for genre photography. This is really a universal and convenient focal length. It is ideally fit for video shooting on modern SLR cameras.
As soft carrying case and a petal hood are included with the lens.
Attention! The autofocus won't function on Nikon D40, D40x, D60, D3000, D5000 cameras which are not equipped with the built-in motor.
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Posted by: Sergei Borodin Date of publication: 17.08.2010