UD Lenses - RF Lens World - Canon Singapore

UD Lenses

Though fluorite offers superior optical characteristics, the high production cost makes it unsuitable for more widespread use. In order to extend ideal performance to an wider range of camera lenses, Canon set out to develop a new type of optical glass with characteristics similar to fluorite. In the early 1970s Canon succeeded in developing Ultra-low Dispersion (UD) glass. Compared to standard optical glass, UD glass exhibits a lower refractive index, low dispersion and excellent partial dispersion characteristics. Therefore, an optimal combination of UD lenses can achieve nearly the same effect as fluorite. The development and realization of these high-performance fluorite and UD lens elements led to the creation of the "L-series" line of "Luxury" high-quality FD-mount lenses in 1978.

In 1993, Canon developed Super UD glass, a dramatic improvement over conventional UD glass. A single Super UD lens can do the job of two conventional UD lenses, essentially offering the same optical characteristics as fluorite. First used in the EF400mm f/5.6L USM lens, Super UD glass significantly reduces chromatic aberration, while also helping to reduce the size of the total lens to improve portability. The exceptional performance of Super UD glass makes it a central feature of many L-series lenses.