;1968: OP Fisheye-Nikkor 10mm f/5.6 (Japan): first SLR lens with aspherical elements. Was a 180° orthographic projection fisheye lens for Nikon and Nikkormat 35 mm SLRs.Kouichi Oshita, "The World's First Aspherical SLR Lens and Orthographic Projection Fisheye Lens: Tale Six: OP Fisheye-NIKKOR 10mm f/5.6" retrieved 11 September 2007 Typical lens elements have spherically curved surfaces. However, this causes off-axis light to be focused closer to the lens than axial rays (spherical aberration) and degrading image sharpness;Horder, pp. 110–111, 113–114Kingslake, p. 322Kraszna-Krausz, pp. 3, 858, 1029, 1439Peres, pp. 176, 716Ray, pp. 48–49Stroebel and Zakia, p. 840 especially severe in very wide angle or aperture lenses. This can be prevented by using elements with convoluted aspheric curves.Kraszna-Krausz, p. 66 Although this was understood since the 17th century,Kraszna-Krausz, p. 840 the grinding of aspheric glass surfaces was extremely difficultKingslake, pp. 4, 15–16Ray, pp. 50–51, 110–111 and prevented their consumer use until the E. Leitz 50mm f/1.2 Noctilux (West Germany) in 1966; for Leica M-series 35 mm RFs.Stephen Gandy, "Leitz 50/1.2 Noctilux in Leica M Mount" retrieved 1 December 2008Peres, pp. 314, 780 The Canon FD 55mm f/1.2 AL (Japan) of 1971 was the first rectilinear aspheric SLR lens; for FD mount Canon SLRs, "Canon Camera Museum: Camera Hall: Lenses: FD Mount: FD55mm [sic] f/1.2 AL" retrieved 1 December 2008Shell, pp. 106, 178 and the Asahi SMC Takumar 15mm f/3.5 (Japan/West Germany) of 1975 was the first rectilinear aspheric wide angle SLR lens; for M42 screw mount Asahi Pentax SLRs (co-designed with Carl Zeiss [Oberkochen]). The use of modern precision molded plastic or glass aspheric lens elements has made aspheric lenses common today.
