The 400mm f/4.0 DO IS USM is Canon's breakthrough in multi-layer diffractive optical lens technology. This sheds new ground for sports, nature and wildlife photographers, giving exemplary results in a size previously unheard of for a lens of such a focal length and aperture. Simply put, the size and ease of handling must be seen to be understood.

Flourite & UD elements eliminate secondary spectrum chromatic aberration High-diffraction optics provide class-leading low size and weight AF Stop function shuts off autofocus when an obstruction appears Dust & moisture resistance made exceptional by magnesium alloy lens barrel and new rear gasket at lens mount Two-stage image stabilization; dual-axis camera shake correction or vertical axis only(for panning) 3-stage focus limiter Focus preset function allows for returning to a specifically set focus by turning a ring in front of the focus ring Full-time manual focus override