Need tips on buying used lens

I'd like to get my first telephoto lens but with how much they cost I'm most likely going to have to purchase a used lens. My question is what should I be looking for other than physical damage on a used lens, what questions should I also ask?

I have bought all of my lenses used and I have been very fortunate in that they have all arrived in absolutely perfect condition. All were bought in the US.
You could ask about physical damage first and then ask if it is possible to see some images taken with the lens. There has to be an element of trust when buying second hand/used. I feel fairly certain that if you buy from here, or FM, if possible, then you will not go far wrong.
Although tempting I would avoid a certain well known auction site as it is amazingly easy to get turned over unless you are aware of the pitfalls.

You could ask about physical damage first and then ask if it is possible to see some images taken with the lens. There has to be an element of trust when buying second hand/used. I feel fairly certain that if you buy from here, or FM, if possible, then you will not go far wrong.

I would agree with Snappa, FM or P.O.T.N. is probably safer these days. If you find you want/need to go with the auction site pay attention to the seller's feedback rating and actually research what they have sold in the past. Most photography buffs have sold photography equipment, not key chains (many sites have been hijacked recently). Reputable sellers with good glass will usually post actual pictures of the lens, from several different angles. Finally, while a pain in the butt relative to fees, Paypal will offer buyer protection on selected items (usually based on seller's established history), thus making the purchase a little safer.

First and foremost ,check the lens for fungus!
This is THE most common issue used lenses have , followed by the chance you are getting someone elses bad example of a lens.

Fungus is easy to check for.Just hold the lens up to strong light and see if there is anything in the glass that shouldn't be there.Most sellers know what fungus is and describe it honestly if there is any.
There is a risk of getting a dud (or partly dud) lens that someone simply want's to be rid of. There is little you can do but get some kind of guarantee from the seller that it has no obvious optical faults.

I think one of the best ways to buy is from members of forums such as these that simply want to upgrade to a better model . Often such lenses are in perfect condition and allready have images posted from them so you know what you are getting optically.
....and they usually go for bargain prices


other things-
Small dust specs are harmeless optically but will reduce resale value slightly.
Small scratches or marks on the body don't nessesarily mean the lens has been abused but watch out for larger marks and dents.

Another reputable seller of used equipment is www.keh.com. I've purchased a couple of used lenses from them and have been very pleased with their service and merchandise.

The standard disclaimer in used lens ads seems to be

'No scratches, haze, fungus, dust, or cleaning marks'

... scratches ... should be self-explaining, note that scratches on the front element might be *very large* before they actually show on your images. Scratches on the rear element are much more critical.
... haze ... if the lens shows some internal fogging, similar to
... fungus ... which is very critical, because it will really destroy the coating on your glass and have an impact on the images. Will grow and normally can not be removed ... I've seen 10,000$ lenses with fungus offered in the 500$ range
... dust ... sometimes gets sucked into the lens, and is not that critical IMO. I don't expect to get a completely dust free lens if I buy some older lens.
... cleaning/scrub marks ... occur when the previous owner is not careful when cleaning his lenses and damages the coating. Might cause additional flare, but is maybe even less critical than scratches on the front element.

NB ... bear in mind that a seller who is either not honest or just illiterate of photography might offer a lens with all the above mentioned problems as 'MINT' or 'MINTY' (my favourite )

And ... of course ... if the AF is working or not. Maybe difficult to say for sure by the seller, as the lens might require adjustment to your specific camera body.

Finally, for older third party lenses (especially Sigma, but also Tamron/Tokina) it should be inquired if they work at all on Canon Dslrs ... it is NOT sufficient that they work on older Canon film cameras. Sometimes some great older lenses are offered dirt cheap ... but they just won't work and can't be made to (otherwise they would be sold more expensively )
Still, it might be possible to use older lenses wide open, it is just not possible to stop them down.

So ... the best advice would be ... TRY IT OUT ON YOUR CAMERA

Best regards,
Andy

If you want to avoid hassle and scams, you can also resort to getting a refurbished lens from Adorama or BH. They go up on the site pretty often and can be had for just a little more than what people consider a "used bargain" (meaning price, not condition). The only thing you won't get is the original box. My feeling usually tells me that a refurb goes through just as much or more of a process than a new lens. You also get a warranty with it and can return it if you don't like it.