FL Mount

FL-F300mm f/5.6

FL-F300mm f/5.6
Marketed March 1969
Original Price 100,000 yen (w/case)
Lens Construction (group) 6
Lens Construction (element) 7
No. of Diaphragm Blades 8
Minimum Aperture 22
Closest Focusing Distance (m) 3.5
Maximum Magnification (x) 0.091
Filter Diameter (mm) 58
Maximum Diameter x Length (mm) 75 x 168
Weight (g) 850

A high performance telephoto lens. This is the first interchangeable lens for SLR cameras in the world, which used artificial crystal fluorite (calcium fluoride/CaF2) lens elements to achieve extremely high contrast correcting chromatic aberration, which is destiny of super telephoto lenses. Fluorite has a crystalline structure and is equipped with extraordinary optical characteristics unobtainable with optical glass - a low index of refraction and low dispersion. It used two fluorite elements. Moreover, the dispersion characteristics of fluorite are nearly identical with optical glass for wavelengths in the range from red to green, but differ greatly for wavelengths in the range from green through blue. Those characteristics enable significantly improve the imaging performance of super-telephoto lenses. "F" in the name stands for "Fluorite".