Originally Posted by M_Six
Got my 400mm f5.6 today. Won't be no hand-held, low-light shots with this puppy, I can tell you that.
Now I need to wait for a clear night or some serious sunshine so I can go have fun with it.
Yeah, too bad that they don't make an IS version. You could hand hold the 500mm with a 1.4X TC down below 1/100-sec., but you need a tripod to do it with the 400mm. For shooting most birds in flight you need a high SS anyway, so the 400mm excells at that. Use ISO 800 as your default for BIF.