From Sigma:
Important Notice
Potential issue of ghost resistance deterioration of the SIGMA 28-70mm F2.8 DG DN | Contemporary
Dear valued customers
Thank you for your purchase and continued support of our products.
We have become aware of a potential issue with our recently released SIGMA 28-70 F2.8 DG DN | Contemporary, which could lead to increased ghosting over time in certain shooting conditions. This falls short of our usual high standards so we are acting as quickly as possible to rectify the issue.
Applicable Product and Serial Number
– Applicable product:SIGMA 28-70mm F2.8 DG DN | Contemporary (for L-mount, Sony E mount)
– Serial Number: serial number prior to 55488834, regardless of mount
The phenomenon has been identified early, so only a small number of customers are affected. Anyone who has already received a 28-70mm F2.8 DG DN | Contemporary (which has only started shipping in some countries) can check their lens’s serial number to see if it is affected.
How to check the serial number
You can find the serial number printed on the side of the lens, and also on the box. If your serial number is higher than 55488834 you can be assured it is not affected by this issue.
Cause of phenomenon
Our optical engineers are working hard to identify and eradicate the underlying cause of the phenomenon, and we expect to have this resolved within a month.
Treatment on this issue
We will suspend all shipments of the applicable product until the cause of this matter has been identified. Once we know the cause, we will be in touch with the small number of affected customers to advise on whether we will repair their lens or replace it, and how this process will work.
In the meantime, all customers can continue to use the 28-70mm F2.8 DG DN | Contemporary with confidence. If you have any questions please contact your local authorized SIGMA Service Station at https://www.sigma-global.com/en/world-network/, who will be happy to assist.
For customers in the US requiring more information, please contact our Service and Support team at info@sigmaphoto.com.
We apologize for any inconvenience this has caused and we assure you that we will put this issue right as soon as possible.
SIGMA corporation