Tamron has issued a product advisory noting that select units of its 70–180mm F2.8 Di III VXD (Model A056) lens for Sony E-mount cameras were shipped without proper calibration of the internal floating optics, which could result in decreased image quality.
The internal floating optics are designed to correct for chromatic aberration when properly calibrated, but according to Tamron’s notice, ‘some lenses have already been shipped out without the value being optimized.’ Tamron says affected units that have shipped will be inspected and adjusted or exchanged for entirely new units.
Tamron doesn’t specifically say what set of serial numbers are potentially affected, but they have set up a dedicated website for entering your unit’s serial number to verify whether your unit is affected. Above is a graphic on where you can locate the serial number of your lens.
Tamron ends the notice saying it ‘sincerely apologize(s) to all users and potential purchasers for any inconvenience this issue may cause […] We appreciate your continued support for our products.’