Buying used gear is always a balance between risk and potential reward. There is always a chance the lens will be defective in some way or another, but there is also the potential that you will get a perfect lens at a great price. When buying online, you are at the mercy of the seller, but when going out to buy used gear in person from local classifieds, there are several things you can do to decrease the chances of getting a lemon.
1. Stiff Focusing/Zoom Rings
Ages ago, I got burned by this one myself! Make sure those rings are smooth. When I fell prey to this easy-to-spot defect, I was thinking in my head that the lens just needed to be lubricated. After a conversation with my local lens repair guy, it turns out that stiff zoom or focusing rings are almost always signs that the lens has been dropped and damaged.
2. Dust or Mold Inside The Lens
Look very carefully through the lens when considering buying it. If there is anything “inside” the lens, consider that the lens might need to be completely taken apart to clean it out. Mold is especially bad. If you see any signs of even dust, though, it is probably worth running away with your money rather than opening that can of worms. Bring a flashlight to blast some light through the lens to make sure you can see anything that might be hard to see.
3. Scuffs/Dents
It is pretty easy for a nefarious seller to clean a lens extremely well to make it look “brand new,” but any slight scuffs or dents in the lens casing can’t be “cleaned” away and are a dead giveaway that the lens may have taken a beating in the past.
4. Poor Focusing
Take YOUR camera with you to see the lens. Mount it and shoot with it. Make sure to zoom into the shot on your LCD and make sure that it is consistently focusing where you have commanded it to. Some lenses can be notorious for back focusing or front focusing, which is something you probably want to avoid.
5. Included Warranty
I can’t believe how many times I see ads claiming that the lens has warranty left that you get to take over when you buy the lens. The vast majority of warranty guarantees only apply to the original purchaser of the lens. Don’t trust a promise of warranty until you have read the lens manufacturer's warranty agreement yourself.
6. Stolen Gear
Knowing when gear has been stolen can be a bit tricky, but there are a few things you can do to spot gear that may have been stolen. Obviously, if the seller has the original receipt, that is ideal, but often isn’t viable. Another great sign that the lens wasn’t stolen is if the seller has the original packaging for the lens, but again, that is often unlikely.
You can also try to get a feel for how “well” the seller knows the gear through common questions such as: “Why are you selling the lens” or “What did you use the lens for?” In most cases, a thief won’t be able to give you good answers or their answers will contain slightly inaccurate information. You could also try asking the seller if the lens would work well for something that you know it wouldn’t to see if they actually know what the lens was designed for. For example, if you are buying a very wide lens, ask if they think it will work well for taking headshots. A real photographer who is familiar with the gear will know it would be poor for that job, but a thief probably will readily agree to get you to buy the lens.
You Can Never Be Too Careful
Buying used gear is always a big risk. Make sure to be careful to avoid being scammed. The best thing to do is to always remain calm and not get too excited when getting ready to buy. Expect to be disappointed and walk away with your money. Never let yourself fall prey to the thought that the lens only has some sort of trivial, minor imperfection that can be cheaply fixed. When it comes to lenses, “cheaply fixed” is a very rare thing.
Unless you see a thick layer of dust (very rare), dust for the most part isn't going to be problematic.
Another thing to check for is if the lens is decentered. I've had this problem before. Depending on what kind of shooting you do, it may not be that problematic, but if you're going to do landscape or architectural imaging, it will.
Every time I see a lens on Craigslist or eBay the seller says the lens is mold and fungus free. Who in the hell is suffering from fungus filled lenses?
Yes, it's odd to list problems the lens doesn't have. "Never been dropped in salt water"
Which must mean it's been dropped in fresh water. Several times. =)
It used to be an issue with older lenses (and can still be with the really old ones), but I think it's just an archaic problem that has stuck around in discussion because of its former prominence.
Dust particles + wet, humid climate = fungus in lens
I have a 2 inch truffel growing in my Nikon 24-70 2.8... I might as well just sell the truffel and buy myself a new lens :P
Three years in Australia didn't do my old Sigma 70-210 f2.8 any favors.
Hit the DOF preview button on the camera to check the aperture blades as well. Make sure their action is smooth and quiet, and the blades free of oil and damage.
"1. Stiff Focusing/Zoom Rings"
The option for this is renting the lens you want, get to know it very well before buying a used one, then you can expect it properly. "Stiff Focusing/Zoom Rings" could also be how the poor construction of all copies of that lens, if you dont know the lens then you won't know.
2. Dust or Mold Inside The Lens
I bought my used Tamron 70-200 2.8 non-VC with dust in it at a great deal, where the vendor was a local fellow photog, where he also bought it used, so the lens was pretty worn but it works very well (not amazing) for headshots, model and portraiture (non action shots). While I'd admit the shots at 2.8 is tact sharp only 1/10 for outdoor naturally lit shots. For $500 it was a stepping stone lens. My other option was to buy a new or used Canon 70-200 f/4, I wanted the f/2.8 that was offered to me, don't regret it ever. It's my primary lens I use ever since I got it 2-3 years ago. If I had the cash I would have sent it in for cleaning though, but I doubt the dust does anything unless shot at smaller apertures like f/22-f/36, when I shoot at f/4 maybe f/5.6 at most on it.
4. Poor Focusing
This is very tough to do in the field testing at the meet up for a sell, even looking at the back of the camera's LCD it is tough to get an accurate sharpness reading on most DSLR LCD cameras. Also note from the research I did the preview in the back of the LCD at least for canon is JPEG, and a RAW file is likely to be sharper as it is not compressed data so if you see its slightly out of focus on the LCD it may be tact sharp on a bigger monitor viewing in Lightroom or photoshop or etc... Only way to truly test sharpness is bring your laptop with your software ready. As well not all lenses are equally tact sharp on every single image, as well may act differently on different DSLRs and who knows if the lens if manually calibrated on the seller's DSLR so you may need to calibrate as well on your DSLR.
6. Stolen Gear
www.Lenstag.com
or I agree of course an original receipt.
I recently bought a 90's Nikon lens 70-210mm. I had to look through a few really crappy ones before I got a clean one for $100. You just have to be patient and be willing to walk away to find the right one.
In last 6 months I bought about 10 old pro lenses (for various reasons - for friend, for repair, for re-selling, for myself…) and I can say that dust is not problem at all. Even brand new lens can have after 2 weeks of shooting some dust particle inside.
The same with scratches on body of the lens, sure, big deep scratches are warning sign, but small cosmetic scratches should not be reason to not close the deal
"Why are you selling the lens?" Is the most annoying question in selling used gear. The answer is never going to be "because I stole it." Obviously the person no longer uses it, wants to upgrade, or just needs the money.
The goal of the question is just to probe for inconsistencies in their answers. No one is going to tell you they stole it but a thief probably doesn't know enough about photography to give good answers. By probing with a few seemingly innocent questions you can get a feel for if this was actually the owner of the lens or not.
Close the diaphragm of the lens and check with a flashlight both sides of the blades for dark spots on the lens indicating that lubricants have migrated onto the blades. This will cause the blades to stick resulting in overexposures. This problem is typically found in lenses that have been exposed to extreme heat like leaving a camera bag in a hot car in the summer. When the lubricants get hot, they can thin out and run. Repair requires disassembly an cleaning of the blades.
I may consider buying second hand but depends on its condition. Everyone looks at the condition initially for there is no guarantee like having warranty protection plan (http://protect-o.com) on brand new accessories.