The Sigma 16mm f/2.8 XQ is an ultra-wide-angle prime lens from Sigma's XQ line, built for 35mm SLRs and typically supplied in interchangeable mounts covering the major systems of its era. As a fast 16mm it was designed for dramatic wide-field work — architecture, interiors and landscape — where both coverage and a relatively bright f/2.8 maximum aperture mattered.

At recent UK auction the 16mm f/2.8 XQ has been a modest performer, with hammer results of £60 in August 2024 and £69 in March 2023, giving a median around £65. As of today in 2026 that narrow band is what clean, working copies are worth at saleroom level, and buyers asking what the lens sells for should treat the mid-£60s as the wholesale benchmark rather than a dealer retail price.