skip to Main Content

Canon Files Patent For New Primes (45mm, 50mm, 60mm)

50mm f/1.4
50mm f/1.2

Egami spotted another patent filed by Canon. The patent refers to s 50 mm F1.4 , 50 mm F1.2 , 45mm F1.6 and 60 mm F1.8 lenses, and describes an apochromatic design that aims to reduce chromatic aberration.

Patent description (machine translated):

  • Patent Publication No. 2013-57802
    • 2013.3.28 Release Date
    • 2011.9.8 filing date
  • Example
    Example
    Focal length Fno. Angle of view Focus
    One 51.7 1.45 45.4 Floating rear focusing +
    Two 51.7 1.45 45.4 Fed whole
    Three 51.7 1.25 45.4 Floating rear focusing +
    Four 51.7 1.25 45.4 Fed whole
    Five 45.0 1.6 51.4 Fed whole
    Six 60.0 1.85 39.7 Fed whole
  • In many large-diameter Gaussian secondary spectrum of axial chromatic aberration
    • This problem occurs when using glass and others with the same Abbe number, a lens that is different partial dispersion ratio
    • When used in a positive lens lanthanum flint glass small partial dispersion ratio
    • When used in a negative lens of flint glass titanium large partial dispersion ratio
  • Canon patent
    • Using a lens with a partial dispersion ratio appropriate correcting the axial chromatic aberration secondary spectrum
    • The concave lens surface adjacent to the aperture, coma aberration correction, the sagittal flare
[via egami]
Back To Top

Notice

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, scrolling this page, clicking a link or continuing to browse otherwise, you agree to the use of cookies.