Thursday, 11 July 2013

So you're buying a second hand lens - what to look for?

When you are buying a second hand lens, it's always a nervous business. Since there is no warranty available it's important to test the lens before you hand over the money. Anyone that won't let you do this is a loser with something to hide. Walk away.

Can you spot the problem with this one?

Note this is not how to review a lens - this is only scoped to a quick test before you walk away with your new glass. There are common problems to all lenses to look for:

  • Dings and scratches in the casing that might indicate it has been dropped;
  • Smooth movement of focus ring both manually and automatically aperture can be set (either manually or auto depending on lens) at all zooms;
  • Look through the lens off camera at its widest aperture and check for no fogging inside no fungus no scratches on the camera end (other end doesn't matter much).
  • It can be helpful to know which parts should and should not move. 
  • If the lens is supposed to be water resistant check that it's gaskets and seals are intact. 
  •  Give it a shake too - nothing should rattle - unless it is stabilised - that mechanism might make a small rattle noise depending on lens brand (e.g. I know Canon IS lenses do). I suppose it would be better to listen for loose things that rattle and roll around when you turn the lens end for end and around. The source of a bad rattle would move the IS rattle would always be in the same place. 
  • Get familiar with the characteristics using a reliable impartial site like dpreview.com 
  • Test the lens on your body at all focal lengths and apertures. 
  • You don't have time to check on computer so use zoom on your camera display. I look mostly for focus and bright spot problems that could be light leakage. Particularly try and shoot into a bright area as this will help show up any dark fringing around the edges of the image.