Skip to content

Canon Patent For 400mm f/4 DO Lens

Canon Patent

Canon Patent

Egami (translated) spotted another patent filed by Canon. It is for a 400mm f/4 lens with diffractive optical elements (to reduce flare).

Patent description (machine translated):

  • Patent Publication No. 2013-64858
    • 2013.4.11 Release Date
    • Filing date 2011.9.16
  • Example 1
    • Focal length f = 392.12mm
    • Fno. 4.12
    • Half angle of ω = 3.16 °
    • Image height Y = 21.64mm
    • 262.14mm length lens
    • BF 69.97mm
    • Two fluorite
  • Materials and anomalous partial dispersion DOE to use, reduce the chromatic aberration
  • Refractive power of the diffractive surface
    • Strong, but can reduce the chromatic aberration of the element itself, flare increases
    • The weaker, other optical element DOE play a role
  • Refractive optical unit
    • DOE anomalous partial dispersion and bonding materials
    • DOE aspherical surface on the opposite side of the
  • Vibration control
  • Inner Focus
[via Egami]
Back To Top


This website or its third-party tools use cookies, which are necessary to its functioning and required to achieve the purposes illustrated in the cookie policy. If you want to know more or withdraw your consent to all or some of the cookies, please refer to the cookie policy.
By closing this banner you agree to the use of cookies.