There is only ONE WAY for this to be legitimate. The seller can send you a "Second Chance" offer, which will take you to an official eBay link where you can purchase the item thru eBay as normal. I sold some golf clubs and the original buyer didn't go thru with the purchase. I went down the line of other bidders sending them a "Second Chance" offer from eBay, they went to the link and paid for it there. So, there is a legitimate way to do this.
I have received MANY scam offers from people representing themselves as the sellers and offering to sell me the item off-ebay, all I have to do is PayPal the money to them or whatever. This is a scam, period. Never respond to these people, instead go on to eBay and report that they contacted you. I'm quire cetain that you'll never see the camera if you buy it unless it's a legit "Second Chance" offer from eBay.