Canon Lens Code

Canon EF 16-35mm f/2.8 USM II © dzignous

Canon have an unique way of documenting their lens manufacturing dates. Looking at the back (mount) of the lenses is a six-digit code, which indicates where and when the specific lens was manufactured.
E.g. - "UY1112"

The first letter 'U' represents the factory that made the lens:

1. U = Utsunomiya
2. F = Fukushima
3. O = Ōita

The second letter 'Y' represent the year of manufacture:

    •    A = 1986, 1960
    •    B = 1987, 1961
    •    C = 1988, 1962
    •    D = 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

The next two digits represent the month of the lens is manufactured. The last two digits are for internal Canon use. Thus the 16-35mm f2.8 L USM II (UX0903) shown was made in Utsunomiya, Japan factory in Sep 2009.

So the next time when you like to know how "old" is the 2nd hand Canon lenses that you are going to buy, take a look here for some general reference.