I apologize for posting this subject here rather than the Sony lens forum but I'd like some input from fellow bird photographers. I saw a DPReiew account of a new Sony 400 F2.8 lens. It weighs about six pounds but Sony says it can be hand held. It sappears to have some "wow" features but costs as much as a used car. Apart from gathering more light can this lens offer greater sharpness/resolution than my vastly cheaper Canon 400 5.6? This is the test: My Canon needs to be within about 10 meters or 33 feet of a tanager sized bird to get really sharp feather detail. From that distance on out feature detail deteriorates pretty quickly though large birds can still look sharp from further away. So my question is can the Sony lens (given "good" not "challenging" light conditions) provide the same feather detail as my Canon at significantly greater distance say at 45 feet? I know we'll have to see some serious testing but what do you think?