The EF 400mm f/5.6L USM Lens from Canon is a high-performance telephoto prime lens designed with portability and easy handling in mind. One super UD-glass element and one UD-glass element minimize aberrations and result in sharp pictures. The lens also has a built-in hood and a detachable tripod mount.
An ultrasonic autofocus motor (USM) enables fast, smooth and silent autofocus and fulltime manual override allows for precise manual focus even in autofocus mode. A two stage focus range limiter is supported by this lens and is applied by a switch on the lens barrel. By limiting the range of focus distance, you can reduce autofocus time and establish focus quicker on the subject within that range. The two available ranges are 11.5' to infinity and 27.9' to infinity. The minimum focus distance for this lens is 11.5'.