Buying a used lens?

[Smitzel269]

NVm, I got this!

 

[Dao]

- Look at the front and back lens elements and see if any scratches , dents.
- Point a flash light and look through the lens and see if you see any umanusual stuff inside the lens. i.e. fungus (or look through a bright background)
- For zoom lens, try and see if the zoom operation is smooth. i.e. zoom ring or push/pull
- Check it the focus ring and make sure you can turn it smoothly
- Check the switches on the lens and make sure they are working and you can switch it easily
- Mount the lens on the body and check lens functions. i.e. AF, IS
- Mount the lens on the body, set the aperture to a larger number (smaller aperture such as f/22), look at the front of the lens and press the DoF preview button. Make sure the aperture open and close smoothly and the blades are free of oils and they looks normal.
- Take a photos in various aperture and view them in your computer if you have one. I usually meet the seller at a public place during the day if buying from local via craiglist.

That's all I can think of now.