Tamron has announced the 12-20mm F2.8 (Model A084), a fast ultra-wide zoom for Sony E-mount and Nikon Z full-frame mirrorless. The number that matters is the wide end: 12mm on a full-frame sensor is a 122-degree diagonal field of view, and holding F2.8 across the whole range puts this lens directly at astrophotography and cramped-interior work. What makes the announcement worth a second look is the packaging. At 119.3mm long and 570g on the Sony mount, this is not the usual full-frame ultra-wide brick.