Canon Files Patent For 28-300mm and 28-135mm lens (reduced chromatic aberrations)

28-300mm f/3.5-5.6

28-135mm f/4-5.6

Next two Canon patents! As usual spotted by Japanese site Egami (translated) This time for a 28-135mm f/4-5.6 and a 28-300mm f/3.5-5.6 lens.The patent is about reducing chromatic aberrations.

  • Patent Publication No. 2012-163746
    • 2012.8.30 Release Date
    • 2011.2.7 filing date
  • Example 4
    • Zoom ratio 4.67
    • 56.11 – – 131.85mm f = 28.21 focal length
    • Fno 4.12 -. 4.89 – 5.77
    • Half angle of view ω = 37.48 – 21.09 – 9.32deg.
    • Image height 21.64mm
    • 242.67 – – 266.43mm 224.00 overall length of the lens
    • BF 55.79 – 70.40 – 82.95mm
    • 20 sheets of 14 group lens configuration
    • Two two-sided aspherical
    • Three low-dispersion glass
    • Four Super UD glass
    • 102.40mm effective diameter of the first surface
    • 5-group zoom negative positive negative
  • Example 5
    • Zoom ratio 10.31
    • 93.64 – – 307.06mm f = 29.77 focal length
    • Fno 3.31 -. 4.71 – 5.85
    • Half angle of view ω = 36.00 – 13.01 – 4.03deg.
    • Image height 21.64mm
    • 263.66 – – 304.01mm 209.34 overall length of the lens
    • BF 61.72 – 89.40 – 106.84mm
    • 18 sheets 12 groups lens configuration
    • Three 3 aspherical surface
    • Three low-dispersion glass
    • 2 UD glass sheets
    • 84.36mm effective diameter of the first surface
    • 5-group zoom negative positive negative
  • In the zoom lens of the positive lead type, reducing the chromatic aberration of magnification of the secondary

More graphs after the break



Perfomance graph 28-135mm


28-300mm

[via Egami]

 

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