Canon Patents 500mm f/4, 500mm f/5.6, 600mm f/4, 800mm f/5.6 DO Lenses

Egami, the Japanese Photography blog spotted a new Canon patent. Four new Canon DO lenses are covered by the patent. These lenses are Canon EF 500mm f/4 DO, Canon EF 500mm f/5.6 DO, Canon EF 600mm f/4 DO, Canon EF 800mm f/5.6 DO.

Canon also filed a patent 30mm f/2.8, 18-90mm f/3.5-5.6, 18-135mm f/3.5-5.6 lenses several days ago. Below are the details of the patent publication of the new DO lense filed by Canon.

Canon Patents 500mm f/4, 500mm f/5.6, 600mm f/4, 800mm f/5.6 DO Lenses







Description and self-interpretation of the patent literature

  • Patent Publication No. 2013-92575
    • Publication date 2013.5.16
    • Filing date 2011.10.24
  • Example
    No. Focal length [mm] Fno. Half angle [°] Total length [mm] BF [mm] Front lens diameter [mm]
    One 584.99 4.12 2.12 420.00 89.03 141.99
    Two 779.99 5.80 1.59 460.00 97.84 134.48
    Three 488.99 4.11 2.53 320.00 61.00 119.00
    Four 488.99 5.70 2.53 280.01 65.01 85.79
    Five 584.96 4.12 2.12 420.00 88.88 141.98

    Image height 21.64mm

  • How to reduce the size of the large-aperture super telephoto lens
    • Effective diameter of the first group with the largest
    • I reduce the number of the first group
      • It is necessary to reduce aberration by increasing the number
      • Can not reduce the aberration and reduce the number
    • I increase a refractive power of the first group
      • The thickness of the lens increases, the effect of weight reduction is canceled
      • Impact of manufacturing error is large high refractive index
  • Canon patent
    • The aspherical in the first group
    • Performing a variance of sensitivity was composed of opposite sign component of the first group, and also, prevent an increase in thickness
    • DOE is provided to correct chromatic aberration with a small number of lenses
    • Inner focus
    • Anti-shake

via: EG