
This lens is an EF 400 f/4.0 DO IS USM lens.
Features
The world's first multi-layer DO element for telephoto lens Small and
light High image quality Image Stabilization for equivalent effect of a
shutter speed of two stops faster Highly resistant against dust and
moisture
Built to our professional standards with fast AF, full-time mechanical
focus and dust and water-resistant construction
The EF 400mm f/4 DO IS USM is the worlds first super telephoto lens
incorporating "Multi-Layer Diffractive Optical (DO) Element", for camera
lenses, and is considered a major breakthrough. The outstanding feature,
being its superb ability to correct chromatic aberrations. By
incorporating this optical element in the optical design the EF 400mm
f/4 IS USM is much smaller and lighter than a comparable lens having
conventional optical elements. The Multi-Layer Diffractive Optical
Element developed by Canon is a milestone optical element possessing the
characteristics of both fluorite and aspherical elements, which has led
to the production of high-performance camera lenses.
Photo Quote: I dream that someday the step between my mind and my finger will no longer be needed. And that simply by blinking my eyes, I shall make pictures. Then, I think, I shall really have become a photographer. - Alfred Eisenstaedt