Thank you for using Canon products.
We recently informed you of a phenomenon in which some images captured by the EF 70-300 f/4-5.6 IS USM lens appear in insufficient resolution. This phenomenon may be seen at the edge of the frame at the 300mm setting when the camera is held vertically.
We are very sorry for the inconvenience that this phenomenon represents for customers who use this lens and appreciate your understanding and cooperation.
The phenomenon described above may occur in EF70-300mm f/4-5.6 IS USM whose third and fourth digits of the serial number are as set forth below.
Serial Number: [nnXNnnnn]
"X"="0" or "1" (except "N"="7")
If the fourth digit is “7”, it is NOT affected.
"n" represents any digit.
Examples of affected serial numbers are: "nn01nnnn" or"nn11nnnn"
Starting from July 18, 2006, we will make inspections and repairs free of charge for customers who are experiencing this phenomenon, so please contact the nearest Canon service center.