Overview

The Canon EF 400mm f/2.8L IS USM is a professional super-telephoto lens known for exceptional sharpness corner-to-corner wide open, negligible distortion, and well-controlled CA and vignetting. Its build is rugged and fully weather-sealed, but it is heavy at 11.8 lbs, requiring a monopod or tripod for extended use. Autofocus is fast and accurate, and image stabilization aids low-light shooting. It suits sports and wildlife photographers who need a fast, durable lens, though the price and weight are significant considerations.