To produce the segments, Canon is drawing on its various optical technologies cultivated through the manufacture of lenses and mirrors, namely grinding and polishing technologies, aspherical surface
processing technologies, and measuring technologies.
Canon used its unrivalled optical expertise to produce an ultra-compact 12x zoom lens that features 11 elements in nine groups, including one aspherical surface
and one ultra-low dispersion glass (UD) element.
Also, by adjusting the pitch (spacing) of the diffraction grating, the diffractive optical element makes possible the same optical characteristics as a ground and polished aspherical surface
, which effectively corrects for spherical and other aberrations.
The avoidance of unwanted decentration is vital, and by combining minimum substance uncuts along with using aspherical surfaces
, optimum results can be obtained.
The lens unit consists of 7 elements in 6 groups with 3 aspherical lenses with 5 aspherical surfaces
Not only was mass-production impossible, but the fabrication of high-precision aspherical surfaces
was costly and difficult.
In the case of telescopes with aspherical surfaces
such as typical Newtonian reflectors, these errors tend to hide within the asphericity.
The new lens also uses a glass-molded aspherical lens element with aspherical surfaces
on both sides for superb image quality throughout the entire zoom range and it features a closest focusing distance of 12 inches at all focal lengths.
The coating can be applied to flat, curved, spherical or aspherical surfaces
for maximum design flexibility.
Featuring 3 aspherical surfaces
and 1 UD glass element in a 13-element optical formula, the new 17-40mm lens delivers image quality equal to the 16-35mm lens.
Two aspherical surfaces
are incorporated for high image quality at all focal lengths, and a Micro USM makes the new EF 28-200mm lens the only zoom in its class to feature Ultrasonic Motor technology for high-speed and silent autofocusing.