When I took out my camera and was about to put the 200mm lens on, one of the guys asked me what's the glass I'm using. I proudly told him "300mm on that one" and stared mounting it on the D300 body. At that point he disappeared in the shed and two minutes later re-appeared with a rocket launcher on a wooden stand in his hand (considering he was wearing green camouflage jacket it just didn't look good...)
"try this one" he said pointing at the rocket launcher... the mighty 2000mm f11 reflex lens by NIKON... 17kg of glass and steel, two knobs, built in filters and great optics... 3000mm on digital!
I put the camera on, get it set up (not an easy task as no tripod would take this monster lens!) and took a few shots.