We have recently discovered a problem with early production samples of the EF24-105mm f/4L IS USM lens in which flare occurs at an unacceptable level under certain conditions. The flare is most obvious in the wide zoom and wide aperture settings. (See attached picture.)
The problem affects all EF24-105mm f/4L IS USM lenses with a control number less than UT1000. With apologies for the inconvenience involved, we ask customers to check the control number on the back of the lens.