Buying camera gear from eBay makes me nervous and I would advise against it (even though I'm sure thousands of people have found good deals this way).
it's really a question of risk.
If you buy from Canon (new or refurb) you know what you're getting and it comes with a warranty.
If you buy from a major used equipment resller (KEH, B&H Photo's used dept., Adorama's used dept. etc.) then you know that (a) a competent person has inspected the used goods and (b) a 'grade' has been assigned to the condition of the used goods and you can trust the grade is fair and accurate. If they tell you it's in like new condition... it's in like-new condition. If they tell you it should only be used for spare parts... you can be sure that it isn't a working lens and should only be used for salvaging spare parts. They're honest -- even when it's ugly.
If you buy from a private seller on say... Craiglist... you can meet that person at a safe location (e.g. a coffee shop) and IF (and this is a big "if") YOU know what to look for, you can inspect the lens for damage, make sure there are no signs of major knocks such as dents or major scratches. Look through it make sure it's clean through and through. Make sure there aren't issues such as fungus or damage to coatings, etc. And then you can connect it to your camera to make sure the zoom ring, focus ring, etc. all work smoothly with no binding... and that the aperture blades work, the image stabilization works, etc. In other words you can check out it out for yourself BEFORE you buy so you know what you're getting (but this assumes YOU know what to look for).
If you buy from eBay... now you've got some limitations. You have to trust that the seller is (a) honest and (b) qualified to KNOW if their equipment is trouble-free. You could have a dishonest seller who knows it's a problem but is going to take advantage of the fact that you can't inspect the gear -or- (b) even if they are an honest seller, they may not even realize the equipment has a serious problem (such as internal fungus on the lens coatings.) This is compounded by the fact that you don't really have any way of checking it out for yourself and have no idea of the qualifications of the seller's ability to fairly and accurately rate the condition of the gear.
I consider eBay to be one of the more-risky places to buy photo gear.
If you saved a few bucks because you found a good deal and won the auction on eBay... but the gear isn't in the condition you expected and now it needs serious work (or a hassle to try to get your money back)... did you really 'save'?
Tim Campbell
5D III, 5D IV, 60Da
......................Tamron.......Sigma. I have all three. I use all three. It's just the way it is.
