Canon Introduces New Smaller and Lighter EF 400mm f/4L DO IS USM Lens

During the manufacture of the Multi-Layer Diffractive Optical Element's diffraction grating, the height and pitch of the diffraction grating as well as its positioning requires micron-level precision (1 micron equals 1/1000 mm). Such exacting accuracy was made possible through Canon's proprietary three-dimensional ultra-high-precision micro manufacturing technologies and the replicated aspherical lens manufacturing technology used in the production of Canon EF lenses. Such advanced technology also makes possible the manufacture of the ultra-precision diffractive optical element.

To make a lens smaller and lighter, the spacing between the elements is shortened and the refractive properties of the front and rear lens groups become more pronounced. This, however, results in increased chromatic aberration. To resolve this problem, the Multi-Layer Diffractive Optical Element is located within the lens to cancel out the occurrence of chromatic aberration. Compared with conventional super telephoto lenses, the EF 400mm f/4 DO IS USM lens, measuring 233 mm in length, is about 26% shorter and, weighing 4.3 pounds (including the 5 ounce tripod collar), about 36% lighter.

The Multi-Layer Diffractive Optical Element placed in the front lens group eliminates chromatic aberration caused by the refractive lens group. Chromatic aberration is thereby suppressed to an absolute minimum. Furthermore, the aspherical effect corrects for spherical and other aberrations, resulting in high resolution and high contrast for outstanding image quality. Available at authorized Canon dealers in November it will have a suggested retail price of ,900.00.

Download the EF 400 DO specs in .pdf format