I just ordered a Sigma 70-200mm OS f/2.8 for my canon 5D. I got a nice price on it and am looking forward to trying it out. I bought it to replace my older Tokina 80-200mm f/2.8, which I will be selling upon the sigma's arrival. It's a nice lens and takes clear pictures, but 80mm is a bit to close for a lot of situations and it does not have internal focusing or IS.