Many photographers choose to purchase used gear and save money because new lenses getting more expensive all the time. The used lens market is often full of great lens choices, especially for someone on a tighter budget.
Purchasing a used lens locally is also a great option because you can have an actual visual and physical examination of the lens before you buy it. Being able to check it out and more importantly put it on your camera and test it is going to be the two most important factors in your decision to buy the lens.
In this article, I will give you some tips on how to check a used camera lens, and to make sure that it is the right one to buy.
How to Check a Used Camera Lens
The first step is to make a careful visual examination of the lens. Look for scratches, dents, and anything that would indicate that the lens wasn’t actually treated gently. If the lens has been dropped or abused, the chances are that some of the glass elements are damaged or that something doesn’t work properly. Examine carefully the following items:
Scratches in the outer glass surfaces on both ends are unacceptable. Angle the glass towards light and look at the reflection. Check for any marks or swirls in the lens’ coating.
Point a small light source like a flashlight at one end of the lens and look through the other end. Is there dust or fungus on any of the inner elements? Although it’s possible for dust to get inside the lens, minor dust usually doesn’t affect picture quality, larger specks or clumps will require an expensive cleaning process.
On the other hand, the fungus is a deal-breaker because it etches the glass and can never be fully removed without a re-polishing.
Lens Mounting and lens terminals
Check the lens mount visually for brassing. While brassing is not a deal killer, but it will tell you that, the lens was not handled well. Check the lens terminals. Make sure the pins aren’t loose and that it doesn’t look like someone did a crappy repair job.
Check the Lens rings
The zoom ring, aperture ring, and focusing ring tend to turn loose with time. In addition, it can be a good indicator that the lens has been dropped or used excessively.
To check this, take the lens and move the focusing and the zoom ring around. If the lens has an extending focusing element, move it around to see if it’s loose. You have to assume that some little movement is normal.
In addition, use manual focus and be sure it’s smooth; if it catches, there could be a problem. The same goes for the zoom; if it catches, there could be a problem.
Ideally, both focus and zoom rings should be smooth and offer some resistance. You should not hear any grinding sounds as you rotate either ring, since that might be an indication of dust or sand inside the lens, which is certainly not a good thing. The lens should obviously be able to run through the whole scale of both focus and zoom rings. If a focus or zoom ring has a dent on it, it may affect the precision and smoothness of operation.
Check Filter Threads
The threads at the end of a lens to accept a filter can often become damaged from not mounting filters correctly, most commonly they get cross-threaded. Alternatively, it can become flat threads due to excessive use. This kind of damage cannot be fixed or repaired. Check that the filter threads have no flat spots and that a filter will screw into them easily.
The second step is to mount the lens to your camera, the reason why it is important to test a lens on a camera is that you will be able to see quickly if there is any potential problem with the lens. A lens might appear perfectly normal on the outside, but it might have mechanical, electronic, and other problems that can only be identified when it is mounted on a properly functioning camera. Then do the following checks:
Check the mounting and connections
Check to see that there’s very little play between the camera mount and lens mount. Also, make sure the camera doesn’t show any kind of error message when moving the lens and holding the shutter halfway down.
Check the lens aperture
Photo by Pixabay
Attach the lens to your camera, then open and close the aperture. Make sure it opens and closes without any hesitations. Make sure that it moves smoothly and has no damage or oil on them. Check if the blades are snappy and without any stickiness that could be a sign of collected oil.
Make sure to test the lens at different apertures. I prefer to shoot at least two images – one at wide-open aperture and one fully stopped down. Inspect the images and make sure that they look properly exposed.
- Check the Autofocus
Use AF and select a focus point; take a sample photo. Review the photo and check focus. If your camera works with every other lens you’ve mounted on it, but not with this one; there’s a problem.
Set the lens to infinity focus and focus on something up close. Does the lens AF as fast as it’s supposed to? Different lenses will have different focusing speeds, but knowing how slow or fast they should be is important. If it’s horribly slow and it’s supposed to be lightning-quick, there’s a problem.
If you are testing a zoom lens, do this for all focal lengths to make sure that autofocus does not lock up at any focal length.
Check lens IS
One of the easiest ways to check image stabilization is to use “Live View” of your camera, Hold your camera like a point and shoot at arm’s length with the lens zoomed out to 300mm.
The image on the screen should be jumping all over the place due to small movements in your hands and arms. Then press the shutter to engage the IS and the image on the screen should settle right down. Another way is you should hear the sound when you press the shutter halfway.
Evaluate the sharpness
If you are going to buy an expensive lens, it is better to check the lens sharpness using a test chart. These patterned charts are easy to find online, and they can be stuck on a wall, or placed on a table, and used to quickly evaluate a lens. A sample of a test chart is shown below
Check the shots on your camera LCD or on the computer, and zoom into 100%, some cameras and lenses will need fine in-camera adjustments for perfection, but any big and obvious un-sharp test results may indicate a lens has been dropped or is out of alignment.
Try to test the full aperture range and look for sharpness from edge to edge.
For more detailed information on this procedure, check my post: How To Calibrate Your Lens- Enhance Autofocus Accuracy
Given how much camera gear is out there, buying used lenses is a great option today. While there is some disadvantage of buying lenses locally, such as your choices will be very limited, and it is difficult to find what you are looking for. The good thing is that you actually see and test your lens.
When purchasing a used camera lens, you have to be as thorough as you can when checking and testing the lens, you will save yourself a lot of money and time in the process.
I also advise you to read some lens reviews, those reviews sometimes list common problems to look out for on used equipment.
Thanks for reading, I hope you enjoyed the article, in case you have any questions just drop them below & I will be happy to answer you.
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