I just picked up a 80-200 4.5 ai lens. Looks nice and a late serial number. But the slop, oh the slop. It focuses and zooms fine, but the focusing ring is so loose. When you sit it on its cap the focus/zoom ring falls right down. Klank. Annoying, mostly. I'm considering returning it (bought it on ebay from someone in Japan - I'm in california), but I got a fair deal and it looks real nice otherwise, and I'm wondering about sending it for service instead under the thinking that any lens this old is going to have something wrong.. It has a fair amount of internal dust toward the front elements. Anyone recommend someone to service a lens like this? Nikon service is a bit pricey, I'm thinking