Patents: 24mm f/2.8, 50mm f/1.2, 300mm f/4

Patents: 24mm f/2.8, 50mm f/1.2, 300mm f/4

New Optical Formula Patents
A new patent showcasing 3 different focal lengths has come to light.

  • Patent Publication No. 2012-8352
    • 2012.1.12 Release Date
    • Filing date 2010.6.25
  • Example 1
    • Focal length f = 294.0mm
    • Fno = 4.14
    • = 8.42deg angle.
    • 15 sheets 11 groups configured
    • One element radial refractive index profile
    • Bowen ratio 0.78
    • Inner Focus (the second lens group for focusing)
  • Example 3
    • Focal length f = 51.5mm
    • Fno = 1.25
    • = 45.6deg angle.
    • Configuration 6 each group 10
    • Two elements radial refractive index profile
    • One aspherical surface 1
  • Example 4
    • Focal length f = 24.7mm
    • Fno = 2.86
    • = 82.4deg angle.
    • Configure each group 11 10
    • One element radial refractive index profile
    • Rear focus (the third lens group and the second lens for focusing)
  • The principle cause chromatic aberration
    • Light is refracted at the interface of the lens
    • Within the lens are not refracted rays
    • The refractive index is different for each wavelength
  • Element and the axial refractive-index distribution is
    • Refractive index change in the direction of optical axis
    • This patented technology is not used (as introduced)
  • Element and the radial refractive index profile is
    • Refractive index change in a direction perpendicular to the optical axis
    • Rays are refracted at the boundary and both the lens in the lens (chromatic aberration occurs).
    • Chromatic aberration can be corrected if appropriate refractive index profile
    • Rather than spherical or aspherical, planar (flat glass), but I (easy processing)
  • Canon’s patented
    • Elements to create a radial refractive index profile optimized for each wavelength the refractive index profile is difficult
    • Patented technology, the characteristics of chromatic dispersion (Abbe number, a partial dispersion ratio) to optimize, to compensate for chromatic aberration
    • Optimize the calculation, line d, line C, line F, to compensate for chromatic aberration of four wavelengths simultaneously in the g-line
    • Create a radial refractive index profile element as a mixture of resin

 Source: [EG]

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