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

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)