I get asked this question quite a bit so I thought I'd do a quick post with my tips. As most of my camera/lens specific articles are, this is focused on Canon brand lenses although my safety tips apply to any lens purchase. First off, buying a used lens is always a gamble, especially when you're spending $7,000 or more on a super telephoto. It may look clean and unused, but is there anything wrong with it? Is the focus off? Does the Image Stabilization work properly? The easiest way to get through this nerve-wracking experience is to buy from a trusted seller.
Who are you buying from?
If buying from someone on eBay, check their feedback. Do they sell lenses frequently? What are past customers saying about their experiences? Is there a warranty being offered? Is the lens genuine USA stock? (This is more important when buying a lens still under a Canon warranty as Canon will NOT honor international warranties for lenses that originated outside of the U.S.)
If buying on Craigslist where you have the opportunity to meet the seller in person (NEVER wire money or send a money order to anyone on Craigslist), bring a camera body with you and take some test shots. Test all of the buttons on the lens. Do they all work? If you're meeting someone in person where you might be carrying a large amount of cash to purchase the lens, meet in a safe area. I recommend people meet at their local bank where they are a customer, simply because of the security cameras and the occasional security guard present. Don't just walk into a random bank though, make sure you're a regular customer and will be recognized as one.
What to look for
- Check the glass for any scratches or blemishes that won't wipe away with a clean microfiber lens cloth. Tiny surface scratches on the front element are less of a concern than scratches or blemishes on the rear, subjective element. If you find any scratches or blemishes on the rear subjective element, walk away! One or two faint surface scratches on the front element, especially on a super telephoto will usually not be noticeable in your images. Any scratch or blemish on the rear element, will be noticeable in your images.
- Switch the lens to manual focus and twist the focusing ring back and forth, listening for any grinding noises or a feel of grittiness. If the ring does not move freely, your lens may have difficulty focusing correctly and this lens should be avoided.
- Take a flashlight and look into down the barrel of the lens from the front and rear. Is there any dust inside? If there is substantial amounts of dust, walk away. If there is a small piece here and there, you should be able to get it cleaned out pretty easily by sending it in for a cleaning. It's normal for an older lens that's a few year old to have a small amount of tiny dust particles in the lens and these can be cleaned out by sending the lens to Canon for a clean and check. If you're a Canon Professional Services member, you can get several of these clean and checks free each year.
- Look for haze, mold, fungus, or other substances on the glass and inside the lens. Look for oil on the aperture blades. If you see any of these things, walk away. While fungus can usually be cleaned by Canon if it's only a small amount, oil on the aperture blades oftentimes requires replacing the aperture blades; a very costly procedure.
- Check the contacts of the lens and the surface around the contacts for excessive wear. If you see a bunch of scratches on the area around the contacts, the lens may have been handled rough. If there are little to no scratches, the lens was likely handled much more carefully, or, used infrequently.
Date Codes
Check how old the lens is. This can be done by looking at the date code that is usually located near the rear lens element. Note, this date code does not appear on every Canon lens and there have been rumors of Canon removing the date code altogether though this has not been confirmed. Some Canon camera bodies will also have this date code, but again, not all of them.
The first letter, let's just say it's a "U", as this is the more common letter, indicates that the lens was made in Canon's Utsunomiya, Japan factory. Prior to 1986, this letter is moved to the last position of the date code.
U = Utsunomiya, Japan
F = Fukushima, Japan
O = Oita, Japan
The second letter, "X", in this example, is a year code that indicates the year of manufacture. Canon increments this letter each year starting with A in 1986 and prior to that, A in 1960 without the leading factory code. Here is a table to make things simple:
A = 2012, 1986, 1960
B = 2013, 1987, 1961
C = 2014, 1988, 1962
D = 2015, 1989, 1963
E = 1990, 1964
F = 1991, 1965
G = 1992, 1966
H = 1993, 1967
I = 1994, 1968
J = 1995, 1969
K = 1996, 1970
L = 1997, 1971
M = 1998, 1972
N = 1999, 1973
O = 2000, 1974
P = 2001, 1975
Q = 2002, 1976
R = 2003, 1977
S = 2004, 1978
T = 2005, 1979
U = 2006, 1980
V = 2007, 1981
W = 2008, 1982
X = 2009, 1983
Y = 2010, 1984
Z = 2011, 1985
* assumption of continuation being made for future years.
The first two numbers, "09", is the month number the lens was manufactured in. Month 02 is February, month 11 = November. The leading zero of the month code is sometimes omitted.
The next two numbers, "02", are meaningless in determining how old a Canon lens is. This is a Canon internal code (that is occasionally omitted).
