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

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

[caption id="" align="alignnone" width="220"] Perfomance graph 28-135mm[/caption]

[caption id="" align="alignnone" width="225"] 28-300mm[/caption] [via Egami]

 

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