But first a little relevant history... in 1968, Nikon used an "aspheric" element in a truly exotic optic designed for photographing skyscapes - the Fisheye-Nikkor 10mm f/5.6 OP. This lens was different from previous fisheye lenses because it produced a so-called orthographic projection (hence the "OP" designation) in which all parts of the circular image were of equal exposure - unlike regular fisheye lenses where exposure falls-off to the edges and with full-frame fisheye lenses in the corners. This was made possible by using a very costly hand-ground and polished aspheric front element. The exercise was extended in 1976 with the unique 58mm f/1.2 Noct Nikkor, an ultra-fast standard lens designed for available-light photography at maximum aperture. Here the aspheric element eliminated coma so that bright point-sources of light would be reproduced accurately and without any image degrading flare or smearing in the near-dark conditions where it would be most used.

Aspheric elements require high precision grinding and polishing because their complex curved surfaces do not conform to the regular shape of a sphere which is much simpler to cast, grind and polish in regular manufacture. The advantages of using an aspheric element are improved performance through the correction of wide-angle distortion and a reduction in the number of elements resulting in a smaller and lighter lens. This costly technology has been increasingly used in the past few years as Nikon has added several professional-grade autofocus, wide aperture, wide-angle prime and wide-angle zoom lenses to its already extensive catalogue.

But then in 1991 Nikon broke the mould in an unexpected way with a mass-produced lens which was priced for the amateur photographer's pocket. The compact Nikkor AF Zoom 28-70mm f/3.5-4.5 zoom lens was marketed primarily to be sold with the previously announced F601 SLR (N6006 in North America)... the lens being small enough so as not to obstruct illumination coverage from the camera's pop-up flash at the wide-angle setting.

Nikon was able to accomplish cost-effectiveness with this mass-market lens by using a new “hybrid” element. This was manufactured by applying a special ultraviolet-cured resin onto a previously formed near-accurate aspheric glass surface which was then bonded together in a precision-ground metal casting. Although the resin used is, in fact, a coating of only a few microns, it is possible to mould it so that the edge thickness is slightly, but measurably, different from that in the centre of the newly formed element... so forming a new aspheric curved shape.

These hybrid elements can be multicoated conventionally, just like their glass counterparts, so helping to improve light transmission and reduce flare while at the same time improving optical performance by reducing distortion to minimum, or certainly acceptable, levels. The use of a hybrid aspheric element also enables the lens designer to reduce the number of elements, thus reducing lens size to 71mm to 82mm by 67.5mm diameter (52mm filter size), and weight to 348 gms with a potential advantage of lower overall cost.