On old lens series, to find out the age of the lens, you can look at the date code written directly. But now, we can read the serial number and date code on the lens.
1. Read based on the lens serial number
Usually there is a 10 digit serial number on the lens.
DD C SSSSSSS
DD is the code for the lens production date .
This date code cannot be confirmed as the date the lens was manufactured, only an approximate date. It could be that the lens was produced later than that date.
For the 3rd digit, the C serial number is roughly translated as Charge. Canon uses this code to indicate a lens requires a specific service update such as firmware.
The last 7 digits SSSSSSS are a unique code to identify the lens, possibly the month the lens was produced.
2. Reading by date code
Since starting the gradual replacement of coding methods in 2008, Canon added date codes to the back of lenses (Not all lenses have them). An example of a code on a lens could be a code like the one below:
The letter “U” indicates where the lens is made.
U = Utsunomiya, Japan
F = Fukushima, Japan
O = Oita, Japan
The second letter "C" is the code for the year the lens was made. This code is not written in number form, but using alphabets starting from the letter "A".
The first two numbers "12" indicate the lens production month code. For example 03 = March, 12 = December. But sometimes this number is written without using the number "0".
The two numbers after "04" are Canon's internal codes which are sometimes omitted. This code is generally known as the date code.
The date code "UC1204" in the image above shows that the lens was produced in Utsunomiya, Japan in December 1988.