Canon Lens EF 16-35mm f/2.8 L III USM is a high-quality wide-angle zoom lens designed for Canon DSLR cameras. It features a constant f/2.8 aperture, which allows for excellent low-light performance and shallow depth of field. The lens is part of Canon's L-series lineup, known for its superior optical quality and durable construction. With its versatile focal length range, it's suitable for a wide range of photography genres including landscapes, architecture, and events.