PS. I looked at 600 mm lens mostly considering birdwatching. For some stuff it is really a must - but on another hand - at some point we all build a line-up of fave lenses to use on a daily basis ... and one cant borrow all of the stuff on his back. At least until a cargo camel goes your way haha. I prefer "no-cargo-camel" option. I believe restrictions also may give benefits.