AT Aspherical Technology

Many of Fujinon's CCTV lenses feature Fujinon's AT, which combines the company's exclusive Aspheric Technology with a new inner focusing system to greatly improve lens performance over conventional designs.

A single aspheric element reduces distortion at wide angles, improves corner resolution, reduces glare and reflections, and allows chromatic aberration to be managed throughout the zoom range, rather than simply optimized at specific points.

Aspheric elements gain their advantages from the way light passes through them. Light passing through the periphery of a spherical element falls on a different point on the focal plane than light passing through the center (spherical aberration). This requires additional elements to correct. Since light passing through aspheric elements focuses at the same point on the focal plane, additional elements are not needed. Lenses with aspheric elements eliminate the additional weight and space required by the corrective group of elements as well as their increased potential for distortion, ghosting, and flare.