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New patent filed by Canon: EF 2.0X TC with DO elements

tc-2.0

Canon filed a patent revealing a 2X teleconverter along with a diffractive optic element. The 2.0x teleconverter can be bit smaller in length.  More details below

Patent Publication No. 2014-145870 (Google Translated)

  • Published Date 2014.8.14
  • Filing date 2013.1.29

Example 1

  • Focal length -109.09mm
  • Magnification 2.00x
  • 4 group 9-lens configuration
  • One plane diffraction plane (the first group)
  • Master lens
  • Focal length f = 293.76mm
  • Fno. 2.91
  • Half angle ω = 4.21 °
  • Image height Y = 21.64mm
  • The overall length of the lens 275.41mm
  • BF 53.79mm
  • 15 sheets 11 groups lens configuration
  • Protective glass 1
  • Rear filter 1
  • UD 2
  • Fluorite 1
 

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