[quh86]

The only lens i bought new was the 18-55 WR kit-lens. In the meantime i acquired used on ebay(not in that order)

m50/1.7
m28/3.5
m135/3.5
CZJ 35/2.4
CZJ 135/3.5
K85/1.8
FA 35-85/ 4-5.6
DA14/2.8
DA16-50/2.8
DA21/3.2

And i must say I am really happy, not only paid i below market prices (at the time) also the quality was mostly as described. only the da14 and the CZJ 35 were a little roughed up.
So to me, checking the seller and closely examining the items proved successful. Though, i always use paypal in case the seller lied about the item.

[TaoMaas]

Almost all of my lenses are used lenses. I've gotten them off Ebay (and before that from the ads in Shutterbug), in pawnshops, estate and garage sales, thrift stores, off this message board...you name it. You just have to weigh the risk with the reward. Step #1 is always to check for fungus. Beyond that, it's mostly a matter of making sure the focus and aperture work. It's harder to check those things with auto-focus lenses because you pretty much need a camera you can use to test the lens.

[dadipentak]

In my view the ability to use vintage/classic lenses with in-body shake reduction is a major part of the joy of shooting Pentax. By definition, you can't partake of that enjoyment unless you buy used lenses.

[Caat]

With older used lenses there isn't a huge amount that can actually go wrong with them. Things like fungus growth and oil on aperture blades and scratches can all easily be checked in person.

That said I have bought an awful lot of lenses second hand online without having inspected them closely. I've never actually had any problems, partly because I always buy from reliable retailers.

[pathdoc]

I have been burned on precisely ONE e-bay lens, and that experience was taken up immediately with the seller and worked out to our mutual satisfaction.

YouTube user The Angry Photographer has quite a few videos dealing with buying used lenses on e-bay, and they are worth a look - it's Nikon-centric without apology, but the general principles are the same.

I tend to go for buy-it-now on e-bay because auctions can get vicious and expensive real fast (and oddly enough, for all his other flaws, Ken Rockwell has some excellent advice on e-bay bidding), but occasionally you come across a lens that has zero or few bids at a dirt cheap price and you can put a bid in before you go to sleep and wake up the owner of a new (to you) lens.

Generally speaking, those who admit to a lens's flaws are reliable.

[boriscleto]

My last eBay lens purchase was a Sigma 39-80 F/3.5. Not a great lens, but one that looked interesting, and I paid less than $30 after shipping. (I've alway been fascinated by the "Stigma" era lenses...)

The lens had some fungus in it that wasn't mentioned in the listing. I informed the seller, and they issued a refund and told me to keep the lens.

[jlstrawman]

I'm just curious how much of a chance you take in buying a used lens.

Only about 20 lenses here, 80% purchased from eBay. No returns needed from any eBay purchase. I avoid
buying any lens where the description includes words such as: appears, looks like, don't know anything about lenses,
etc. I also generally avoid eBay buying from obvious online thrift stores/estate sellers, etc.

[csa]

I've purchased all my used lenses right here on Marketplace, and have not been disappointed with them. All of them are in pristine condition. Photos and asking questions narrow down the chances of getting a "bad" lens. Of course it can happen, but I think Marketplace is a great place to buy used.

[dadipentak]

Photos and asking questions narrow down the chances of getting a "bad" lens.

Also, most of the 'opposite parties' I've dealt with in the Marketplace had a searchable and reassuring record on the Forum.

[csa]

Yes indeed; this certainly is a valuable resource, as well!

[Kerrowdown]

How much of a chance do you take buying a used lens?

So much depends on the source of the lens... I must admit that I've always usually handled mine before purchase.

[pathdoc]

I cheerfully admit to being a cheapskate with online purchases (though I've almost uniformly made good ones) but being prepared to pay more over the counter where I can handle the lens myself and take it back if there are major issues. If I lived in a major city with camera stores within easy reach (or if I had become more enthusiastic about LBA a lot earlier when I DID live in a major city) I too might have handled my used lenses in person before handing over money.

[Na Horuk]

I've been lucky with my used lenses. All were in good condition. I bought them from total strangers from other countries, even other continents, online, without seeing the lens. I made sure the photos of the lens (and taken with the lens) looked good, and I wrote down the serial number to compare it to the one on the lens (to make sure I get the lens from the photos, and not a switch). I then tested each lens to see if it focuses well (infinity, close focus, focus ring smooth), if aperture ring works (if it moves right, if the aperture lever moves the blades correctly), and that the lens is not decentered, that it is nice and sharp. Granted, I haven't bought a lot of used lenses, but the couple that I have (7, but i got four of them in pairs) have all worked pretty well.
Yes, two developed problems with aperture some months after purchase (in one case probably caused by a friend that used the lens for a bit), but those were over 30 year old lenses, so its not completely unexpected. The glass was great and once the aperture was fixed, things work well.
That said, if you want to get amazing glass dirt cheap, that is a bit of an illusion. It can happen, but it is not a regular occurrence. Often you will have to service old glass if you get it at a low low price, which can double the price.

OH, and one other thing. I make sure the seller is reputable. By that I mean that a) they have been doing this for a while (many user reviews from different countries) b) that they have good reputation/rating and c) that they have a real address, store name that I can call up or visit (even if its in Hong Kong and I will never actually visit, I just want something more than a fake address)

[edmundrt]

I've bought ~30 used lenses, from 5 to 60 years old, mostly on eBay and mostly without any problems at all. The key thing to keep in mind is that it's like buying anything else used - it will likely not be perfect. As a student I don't have the cash to buy expensive new glass most of the time, so I've learned that what doesn't look perfect often performs brilliantly. If it was a great lens when it was new, it is still likely to be a great lens unless it has something seriously wrong with it. If it was a dog when it was new, it's probably still a dog.
On the subject of risk, out of those 30 or so lenses I've had two that were worse than I expected and these were both incredibly cheap purchases from non-photographers who had found them in their attics - i.e., I took a chance on those and was prepared for it. Every used lens I've bought from a good seller who knows what the item is and has described it properly has been a good, and mostly inexpensive, buy. In most cases, old glass in tough enough, and new glass is new enough, that things will turn out ok. Of course, I may have been very lucky and YMMV but I wouldn't be too scared about buying used. And part of the joy of the Pentax system is backwards compatibility, right?
Best thing to do is find a lens you fancy then check out online sources and find out if it has any known issues (e.g. wonky apertures on old East German lenses) and make sure you find a good copy - a good seller should be happy to answer your questions and provide extra photos of the lens, for example. Of course, a good place to start when it comes to good sellers is our very own marketplace, which is full of knowledgeable fellow enthusiasts who want to share the love. That's where I'd start.

[Audi 5 cyl]

Well, this really depends on your needs. My primary source is ebay, but my needs are specific. I never pay market price for anything so all of my lenses are bargains and I often buy lenses and cameras that need repairing rather than cleaning. Sometimes I even buy stuff just to tinker around them like other brands with similar register distance or for pieces. Lets say that from about 120 lenses I ever bought, about 85% i've managed to get to the 100% functionality. I currently own about 70, I've scrapped about 10 and the rest I gave away to friends.

I guess if you want to be sure that you get the good product and you are paying big bucks, you should buy from reliable seller and always ask for sample photographs, ask a lot of questions and why not require a video that demonstrates the operation of the lens. Many sellers have reacted positively to my requests of this kind.