What To Look For When Buying A Used Lens

[JLC]

Hey All,

Hopefully I can get some advice on things to look for when buying a used lens.
I found a used lens I want to buy on Craigslist but i'm afraid i'm not exactly sure how to examine it, and what to look for to make sure the lens is in as good shape as it should be.

Anyone have any tips? Or even better, maybe I can meet the buyer at one of these shops one of you guys work at and have you give it a lookover?

Any advice would be great!
Thanks

[freesole]

A few things, I would look for anything cosmetically wrong with the lens first (ie. look at the barrel and glass, both front and back, for any dings, marks, scratches). Always bring your camera body to test the lens on. Try focusing on a number of objects to ensure that the autofocus is function properly. I would also try it at different apertures too.

Then examine your pictures using the zoom function to see if the pictures were in focus the way you had shot it (some lenses have focus issues which might be able to be fixed with a newer camera body but it's good to make sure anyhow).

[Senna4ever]

Which lens is it? Is it a newer AF lens, or a MF one?

[LiquidTurbo]

You could also bring a laptop to inspect the picture quality to see if you are happy with the results!