Canon has released the new EF 70-200mm 2.8L IS. The new lens sports the new IS which provides up to 4 stops of correction, up from 3 in the previous generation. Designed to be faster and better quality than the previous generation, the lens sports 5 UD elements to reduce CA. With the 1Ds Mk IV coming at 32mp, an update was probably necessary to keep the latest cameras in the sweet spot.
http://www.usa.canon.com/consumer/controll...delTechSpecsAct
