Incorporating Canon?s second generation Image Stabilization technology, this telephoto zoom responds in as little as 0.5 seconds, while providing up to three stops of correction for camera shake. Its AF system has been refined for better response time and tracking speed. And even the new 8-blade circular aperture offers a more pleasing out-of-focus image. Constructed to pro standards, this fast zoom is also highly resistant to dust and moisture, too.Focal Length & Maximum Aperture 70-200mm 1:2.8 Lens Construction 23 elements in 18 groups Diagonal Angle of View 34