Canon EF 400mm f/4.0 DO IS USM Overview

The Canon EF 400mm F4.0 DO IS USM was the first Canon lens to offer diffractive optical lens technology, which is designed to give high optical quality in a considerably more compact and lighter package than would be possible using conventional elements. As well as the fancy optics, this lens also features image stabilization for a 2-stop shutter speed advantage, a ring-type ultrasonic focus motor and dust and moisture-sealing. Optically, this innovative lens is bettered by Canon's more conventional telephoto primes, but the 400mm DO's compact dimensions and comparatively light weight make it a good choice for sports and wildlife photography.