The first EF lens with a zoom range from 100mm to 400mm, the EF 100-400mm f/4.5- 5.6L IS USM lens offers high resolution, superb contrast, neutral color balance, and Canon's original built in Image Stabilizer function. High zoom magnification is achieved by means of a 6-group configuration with 5 movable groups. Fluorite and Super UD glass completely eliminate secondary spectrum for superb color rendition. Autofocusing is fast and silent with Canon's ring USM, and AF speed is further enhanced through an advanced, lightweight rear focusing design that incorporates a floating element for consistent image quality at all focusing distances from 5.9 ft. to infinity.

This lens is also equipped with a dual-mode Image Stabilizer suitable for panning as well as stationary subjects. With full-time manual focus, one-touch zooming with a wide grip, and a special ring that permits adjustment of zooming friction, this is a lens that's extremely easy to use, and ideal for a wide variety of applications including nature, wildlife, sports, and documentary photography.

PhotoZone Review: http://photozone.de/8Reviews/lenses/canon_100400_4556_is/index.htm

The-digital-picture.com Review: http://www.the-digital-picture.com/Reviews/Canon-EF-100-400mm-f-4.5-5.6-L-IS-USM-Lens-Review.aspx

PBase Samples: http://pbase.com/cameras/canon/ef_100-400_45-56l_is