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[Patent] Canon 135mm f/2.8 and a 180mm f/3.5 Using An Apodization Filter

135mm f/2.8

180mm f/3.5

Japanese site Egami (machine translated) spotted another patent filed by Canon. This time it is about a 135mm f/2.8 and a 180mm f/3.5 lens. The news are an apodization filter that should help provide a more pleasant bokeh.

  • Patent Publication No. 2012-128151
    • 2012.7.5 Release Date
    • 2010.12.15 filing date
  • Example 1
    • 137.2mm – f = 135.0 focal length
    • Fno 2.83 -. 3.90
    • 9.1 deg half each painting.
    • Image height 21.60mm
    • 186.7mm – 150.0 full-length lens
    • BF 47.4 – 80.7mm
    • Lens Construction 10 elements in 7 groups sheet
    • 1 UD glass sheet
    • 0.25 times the maximum magnification ratio
  • Example 6
    • 179.1mm – f = 180.0 focal length
    • Fno 3.50 -. 4.00
    • 6.9 deg half each painting.
    • Image height 21.60mm
    • 218.0mm – 199.8 full-length lens
    • BF 70.0 – 89.8mm
    • Lens Construction 11 elements in 7 groups sheet
    • 1 UD glass sheet
    • 0.11 times the maximum magnification ratio
  • (Bokeh) out of focus look of the important
  • Apodization filter
    • The periphery of the filter transmittance is reduced
    • Added to the luminous flux intensity distribution
    • Bokeh is beautiful and the outline of the
  • Apodization element variable
    • If the liquid of same refractive index as the shape of the interface, no variation occurs in aberration
    • To be the same refractive power of the two liquids, the Abbe number is difficult
  • Canon‘s patented
    • Variable element shape
      • Voltage is applied, changing the shape of the interface
      • Obtain the effect of apodization
      • Varying refractive power, the Abbe number
    • To reduce the time variable aberrations of shape
      • By a twist of the material performed, to optimize the absorption coefficient, to suppress the generation of aberration to moderate the curvature of the interface
      • To reverse the two materials (such as liquid), the amount of chromatic aberration, do the negation
      • Suppress the two materials (such as liquid), refractive index, the difference between the Abbe number
    • The entire feeding (with floating)

 

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