Back in March, Sigma published a service notice for the newly-announced 28-70mm f/2.8 lens where ghosting resistance may deteriorate in some circumstances. The company delayed shipping it in order to address the issue, and now Sigma has shared a follow-up notice, confirming it has addressed the issue and will replace affected units, free of charge.

“As a result of our investigation, there is a possibility that the ghost resistance will deteriorate with some products from the initial lot,” the company writes. “In addition, since we have confirmed the countermeasures by process management regarding this matter, we would like to inform you that we would like to collect all the products with the target serial number and replace them with new ones.”

In the initial notice, Sigma noted that it believed that the issue was specific to SIGMA 28–70 f/2.8 DG DN Contemporary lenses for both L-mount and Sony E mount with serial numbers prior to 55488834. The company is sticking with that assessment after looking into the issue and offering to collect and replace any lenses that have made it into the wild that fit that description.

To check the serial number of a Sigma lens, customers can either find it printed on the side of the box the lens was sold in or etched above the Sigma logo on the side of the lens as shown in the graphic below:

Sigma requests anyone with a lens within the serial number range to contact their local authorized Sigma service center using its dedicated webpage to get the unit replaced.