Canon EF 16-35mm f/2.8L USM Ultra Wide Angle Zoom Lens  

To meet the growing demand of digital SLR owners, this ultra-wide-angle zoom offers a broader view, fast aperture, and closer focusing down to 11 in. (.28m). The first EF wide-angle zoom to combine three aspherical elements and Canon's UD glass, the lens remains compact while providing superior image quality across its range. Constructed to pro standards, it's also highly resistant to dust and moisture.
Specifications
Construction 10 groups /14 elements
Angle of view 108° 10' - 63°
F stop range 2.8-22
Closest Focusing Distance 0.28m / 0.9ft.
Maximum Magnification 1:4.5
Filter Size 77mm
Dimensions (Length x Diameter) 3.3" x 4.1" / 83.5 x 103mm
Weight 1.3 lb. / 600g