« on: December 27, 2012, 06:32:09 PM »
I bought all of my lenses used, except for the EF-S 18-55mm and EF-S 55-250mm, which were bought in a kit with my first DSLR. It was really a waste of money...
I had bad luck with the EF 35L. The autofocus is off and needs a lot of AFMA (+17), which was not possible with my 450D when I bought the lens. So this was rather disappointing but didn't stop me. 1 out of 12 used lenses is OK for me and I saved more than 3000€ in the meantime.
I bought used lenses from camera shops, ebay and members in camera forums. There is a large German forum about DSLRs in which you can find dozens of used lenses every month. At ebay you can at least check the seller's reputation. In a forum you need to trust your common sense. I always ask first if the lens is still available, then what kind of payment methods are available etc. and then decide to buy it or not. The conversation, which develops through the exchange of several PNs can tell you quite a lot of a person, e.g. his full name and address (if you ask for it).
In the end you need to decide if it is more important for your to save 30-40% or have a warranty. If you want to save at least some money (maybe 10-25%) and have a warranty, buy from a commercial seller. At least in Germany they have to give you a 1 year warranty on used goods and if you bought it on the internet/by phone, you can send it back within the first 14 days without giving any reasons (local law in Germany: §§ 355 ff BGB).