The EF 100–400mm f/4.5–5.6L IS USM is a professional EF mount telephoto zoom lens introduced by Canon Inc. in September 1998. It is a high performance tele-photo lens ideal for sports and wildlife photography which has received high ratings from purchasers at Amazon.com[1] and B&H Photo Video. Photographers using APS-C cameras must apply a crop factor of 1.6x, giving the lens a field of view equivalent to a 160–640mm lens.
This lens is compatible with the Canon Extender EF tele-converters on newer EOS bodies. Auto-focus works with the 1.4× Extender (and only with cameras that can autofocus at f/8) and image stabilizer (IS) works with both 1.4× and 2× Extenders.