Canon EF 24-70mm f/2.8L USM AutoFocus Wide Angle Telephoto Zoom Lens      

Incorporates many advanced and exclusive Canon Lens Technologies to provide improved performance, including the use of two different types of Aspherical lens elements, and a totally new UD (Ultra-Low Dispersion) glass element for obtaining sharper image quality. Canon's original ring USM (Ultrasonic Motor) makes autofocusing fast, accurate and silent, down to a reduced minimum focusing distance of just 15 inches. The Lens is now sealed against dust and moisture
Specifications
Construction 13 groups /16 elements
Angle of view 74° - 29°
F stop range 2.8-22
Closest Focusing Distance 0..38m / 1.25 ft.
Filter Size 77mm
Dimensions (Length x Diameter) 3.3" x 4.9" / 83.2 x 123.5mm
Weight 2.1 lbs./ 950g
Notes Front Focusing method, UD (Ultra Low Dispersion) Glass