Just had my 300/4L IS and 6D take a tumble off my strap (the clip I used wasn't shut all the way, my bad). Took a 3-4 foot drop. Luckily the lens hood was out. Dented the hood, fixed with a bit of force. Bent the lens slightly, also fixed with a bit of force. Might be getting my CPS membership soon and sending both in for cleaning/check up just in case, but IS, and AF work fine still. MF ring is a tiny bit tighter, but no harm to the actual camera or lens elements. Wooh, metal body and L lens!