[Godel_unicode]

> but it's a genuine Canon lens

How do you know this? More to the point, how does an amateur buying their first lens ever know this?

My friends and I used to buy surprisingly good deal products on Craigslist and see how long it took to determine if they were fakes or broken. It was always one or the other.

[myself248]

I've found a reputable local shop that I trust. In addition to a lot of new stuff, they sell used gear (possibly on consignment?), which means they've got some experts who'll do valuation on it. They have a largely professional clientele and a reputation to uphold, so I think they're trustworthy.

I'm sure I could take a lens to them and have it checked out for a few bucks, or have them broker a sale between me and another private party. Knowing what I'm getting has its own value, and I'm not opposed to paying someone for their time and expertise.

tl;dr: I don't, personally, know that. I trust someone else to know that.

[Godel_unicode]

So it sounds like we agree then; the second hand market can be quite dodgy and you need expert help to be sure you're not being ripped off.