How do I know if a lens is genuine?

Question

I'm in Times Square shooting the Imagine Cup event, and several people said that to fix my shot, I would need a faster lens. Just for the hell of it, I went across the street to a photo shop to see if they had the lens, and what they would be willing to sell it for. The price they quoted though, is kind of unbelievable. Particularly given that on Manhattan Island I would expect pretty much everything to be more expensive.

I'm concerned that I would be walking right into a ripoff of a refurb'd, used, or "grey market" lens. But I don't know enough about what the legitimate lens looks like to tell. What things should I look for to distinguish a legitimate lens from a fake one?

Answer

Both refurbs and "grey" lenses are genuine. The only way you could tell the difference from a US made new one is if you had a list of serial numbers for each category.
Fakes are more easy to spot, will usually have clearly inferior materials and often (deliberately) missspelled brand names (so the seller can claim he wasn't trying to scam you, you made a mistake in misreading the name. Something that may not hold up in court when the actual trademark owner sues, but will hold up (probably) if you'd sue). Think fake "Louis Vuitton" bags sold as "Louie Vutton", Nikon might be changed into Nikkon. For the very best fakes though, it'd take good knowledge of the real thing to tell the difference. But this being Manhattan (New York in general, long home to very shady camera stores) I'd not trust anything offered at much under manufacturer RRP.

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