i'd be fighting tooth-and-nail on this one if i was you. i'll mention things that others have already said, but i want to explain how i'd go about it.
make sure you have all of the correspondence between yourself and the buyer and that you document it thoroughly when submitting it to paypal.this includes any emails between the two of you, ebay messages, tracking details etc.
i assume from what you've said that the buyer has opened a paypal dispute for "item not as described?"
go through the buyer protection policy here - https://www.paypal.com/au/webapps/mpp/ua/useragreement-full#Schedule_1_PayPal_Seller_and_Buyer_Prote... and find whatever you can to disprove what the buyer is claiming.
obviously, a long time has passed so anything could have happened to the camera during that time - including wear and tear due to the buyer's use, damage on the buyer's behalf etc. the fact they left feedback as well is extremely important as it shows that they were satisfied with the item when they received it.
you'll notice also that the paypal wording for buyer protection is "significantly" not as described.""
make sure you spend the time necessary to formulate your argument and submit everything in a clear and concise manner. it's worth it when you're talking about presumably hundreds of dollars. don't forget, the person who is going to be reading through the material from paypal knows nothing about the transaction or the item - so the simpler you put it the better. mention dates, times etc.
if you go to the effort of putting your response together well and all the buyer is saying is "one-liners" then this will help prove you are professional and you have done the right thing.
have someone look over what you've said and make sure it makes sense to them and see if there are any glaring errors.
i've found if you follow these steps with claims (i've only submitted a few of them over the years), you won't lose. i haven't lost one yet.
just be detailed and honest and use all the ammunition you have :] good luck! keep us updated!
