Buying used lenses is a great way to save some money, yet get a perfectly good piece of gear. But you want to make sure that the lens you’re buying is in good condition and that it will serve you well. Some problems are easy to spot, but others can be very sneaky and you may discover them too late. So, before buying that second-hand lens, make sure to watch this video from ZY Productions. It will tell you about seven things you should check to make sure that the lens is worth your money.

Keep in mind that most of these factors don’t necessarily make the lens unusable. But, they change its value and thus you can at least want to ask for a lower price if you plan to buy it. Also, some of the flaws can be repaired, but it’s expensive, so it’s not worth buying a lens that has them. So, here are the seven things you want to check before you make a purchase:

1. Front and rear element

First and foremost, look for chips and scratches on the front and rear elements, as they’re the exposed parts on the lens. If there’s a UV filter, remove it to inspect the lens. If there are any defects, they can show in your bokeh or create strange flares. Although, in some cases, it’s difficult to spot them in photos. Just remember that Canon 70-200mm f/2.8L IS II with a fly inside of it or that heavily scratched lens I wrote about recently.

2. Lens barrel

Next, check the lens barrel for scratches. Some of them are just cosmetic but look for deep scratches and dents. They can tell you if the lens has been dropped.

3. Lens mount

Take a look at the lens mount and check how worn out it is. There’s a great comparison in the video so you can see a difference between a worn out and a well-preserved lens mount. This won’t affect the image quality, but it tells you about how much the lens has been used.

4. Zoom and focus rings

You may see some loose rubber on the zoom and focus ring. This is relatively common and it can easily be replaced. However, you should listen and feel to any grit that may have entered the rings: there shouldn’t be any grinding noises when turning the zoom and focus rings. In focus-by-wire lenses, check if the manual focus works properly.

5. The inside of the lens

Just like checking the outside of the lens, check the inside too. Look for dust and fungus inside the lens by pointing it at a light source and looking through it. While doing this, make sure that front and back elements are squeaky clean so you can be sure that any dust or fungus is inside the lens. Most of the time, some dust doesn’t affect the image. Still, you should take a test photo to see if it shows up in the bokeh. Now, to be honest, it’s very likely that you’ll find some dirt inside the lens. This is especially the case with vintage lenses, and they’re also often subject to fungus. It can be cleaned though if you’re up for disassembling the lens.

6. Autofocus

If you’re buying an autofocus lens, you want to make sure that AF works properly. Of course, you’ll need a compatible camera to mount the lens onto it so you can make this check. Keep in mind that sometimes the lens needs AF fine-tuning, so don’t freak out if it doesn’t focus where your camera tells it to. This happened to me when I was buying my last lens, and it wasn’t even second-hand. After DIY calibration, it works like charm on my Nikon D7000:

7. Aperture mechanism

Finally, check the aperture mechanism to make sure it’s not worn out. The tricky thing is that the lens acts perfectly normal when it’s wide open. But when you stop it down, you’ll notice if there’s a problem. Also, the aperture blades sometimes jam in the stopped down position, so take test shots at different apertures to make sure that this doesn’t happen. Do you prefer buying used or new lenses? And do you have any tips you’d like to add? [7 Things to Check For When Buying Used Lenses via FStoppers; lead image: ShareGrid on Unsplash]