Canon 20mm F2.8 USM EF - Description:
The canon 20mm f2.8 is Ultra-wide-angle lens for serious applications. 20mm f2.8 of Canon lens is easy to hold and carry at 14.3 oz. (405g). Floating rear focusing system. Sharp images are obtained at all subject distances.

Canon 20mm f2.8 is an excenlent lens from optics to handling to build quality and capable of serious landscape, low light and some architecture work. Of course for the last, the Canon EF TS 24 mm f/2.8L is more appropriated, but it costs at least twice as much of the price of the EF 20mm f/2.8. If you're going to use it on a tripod and/or stopped down most the time, the EF 20-35mm f/3.5-4.5 zoom is likely a better option. However, if you are too picky about image quality, be aware that sharpness and distortion when wide open are said to be not as good as in the prime.

Key Features

Ultra-wide-angle lens for serious applications.
easy to hold and carry at 14.3 oz. (405g).
Lens has Floating rear focusing system.
Sharp images are obtained at all subject distances with Lens.

Specifications

Focal Length : 20mm
Maximum Aperture : 1:2.8
Lens construction : 11 elements in 9 groups
Diagonal Angle of View : 94º
EF USM Lens got Rear focusing system
Closest Focusing Distance : 0.25m / 0.8 ft.
Filter Size : 72mm
Max. Diameter x Length, : 3.1" x 2.8", 14.3 oz. / 77.5 x 70.6mm,
Weight without packages : 405g

Accessories included

Canon front & back caps.
Canon 20mm f2.8 lens Instruction manual.