Hello all, Im in need of your advise for information on the 300mm f/2.8L for wildlife? Birding and what everelse might happen to pop up in nature. I just purchased the 400 f/5.6L and im not to impressed with it at all have been using it for about 1.5 weeks. Can return to BH. Im giving the 300mm f2.8L some very serious thought as I can purchase a used lens for about 3K. Thats the top of my price range. Ihave the 1.4TC and was wondering about losing any sharpness with this or the2xTC for that matter. Ihave read that 1.4 good 2x got mixed reviews. I shoot with a 40D. Your info would be very helpful. Thanks