Optics manufacturer Tamron has issued a product advisory informing consumers that three of its E-mount prime lenses suffer issues that prevent them from using autofocus when shooting videos on Sony a7 IV camera systems.

The announcement, published by Tamron Japan, says the company has confirmed its 20mm, 24mm and 35mm F2.8 Di III OSD M1:2 lenses, released in 2019, have an autofocus issue when paired with Sony’s full-frame a7 IV camera system that causes the lenses to switch from ‘AF’ to ‘MF’ when shooting movies.

Tamron suggests it isn’t sure what’s happening, but hopes to fix the ‘phenomenon,’ saying ‘We are currently investigating and will provide details on the “Support Information” page at a later date.’ Based on the problem, it would seem a simple firmware fix could address this issue.

You can keep tabs on the latest announcements via Tamron Japan’s Support Information page.