Canon celebrates 50th anniversary of lens employing synthetic fluorite

Canon Inc. and Canon Optron, Inc. today announce the 50th anniversary of the release of the FL-F300mm f/5.6 (released in May 1969), the world’s first lens for consumer interchangeable-lens cameras which employed synthetic fluorite. Alongside Canon’s interchangeable-lens range, synthetic fluorite is also used in a wide selection of Canon’s optical products, including broadcast lenses and astronomical telescope lenses.

When combined with optical glass, fluorite - the mineral form of calcium fluoride (CaF2) - can correct chromatic aberration to such a degree that it is near non-existent. However, naturally occurring fluorite crystals are too small to be of practical use in photographic lenses. To create the vivid, subtle rendering - not possible with typical optical glass - Canon turned its attention towards effectively harnessing fluorite early on. The Canon F Plan commenced in August 1966 with the aim of developing a high-performance lens that employed fluorite, setting in motion the company’s commitment and development of high-performance lenses.

In 1950, a technique for synthesising fluorite with naturally occurring fluorite crystals was discovered, which paved the way for its use as an optical material. However, a vacuum environment at temperatures above 1000 degrees Celsius was required to cultivate fluoride crystals, which caused many in areas such as installation and manufacturing, to achieve the mass production of large-size high-purity crystals.

Fueled with a desire to develop high -performance lenses, Canon succeeded in the first fluorite crystals synthesised in an electric furnace in March of 1967, and in February of 1968, established synthetic fluorite crystal production technology. At that point in time, fluorite could not be polished like typical optical glass. Canon therefore developed non-conventional machining technology capable of polishing the delicate material, which took four times as a long. In May 1969, Canon’s first interchangeable-lens employing synthetic fluorite, the FL-F300mm f/5.6, was released. Since then, the use of synthetic fluorite has been crucial to Canon’s development of high-performance lenses.

In December 1974, Optron Inc. (now Canon Optron) was established to commercialise the fluorite crystal mass production technology Canon had cultivated. Canon Optron developed a variety of other optical crystal materials while refining its high-temperature vacuum and temperature control technologies for the mass production of synthetic fluorite. In July 2007, Canon Optron provided 12 lenses to the Smithsonian Astrophysical Observatory - including a synthetic fluorite 40cm wide lens, capable of registering signals from over 10 billion light years away.

Canon is committed to improving its imaging technologies, with a focus on optical performance, to ensure its imaging solutions meet the high expectations of its users. Canon will continue to develop and manufacture reliable products, with enhanced optical performance, which play such an integral part in society.