Not my ad, I just happened to see it tonight, and it's a couple hundred dollars less than I usually see these going for. I'd probably go for it myself if I had a little more cash, so I thought someone else here might be interested.

http://boulder.craigslist.org/pho/1444625011.html

That fella seemed a bit confused on lens factors, etc, so I emailed him to hopefully enlighten him and wish him good luck on the sale!