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Monday, March 3, 2014

Canon EF 600mm f/4L IS III and EF 600mm f/4 DO IS




Egami, the Japanese photography blog has discovered two patents Canon filed for a new EF 600mm f/4 lens. Suggestions have been made these lens may be aiming for the 2020 Summer Olympic Games in Tokyo and Rio de Janeiro in 2016. In my earlier post, I have made some observations on Canon and suggested they introduce more DO lens in the future. MichaelDanielHo.com

Patent Publication No. 2014-26210

  • Publication date 2014.2.6
  • Filing date 2012.7.30

Example 1

  • Focal length f = 588mm
  • Fno. 4.12
  • Angle of view 2? = 4.22 °
  • BF 56.0mm
  • Total lens length 374.7mm
  • Inner focus

Example 5

  • Focal length f = 588mm
  • Fno. 4.12
  • Angle of view 2? = 4.22 °
  • BF 55.0mm
  • Total lens length 343.5mm
  • Inner focus
  • Diffraction optical element

Effect of the glass material

  • Fluorite (Fluorite)
  • In the long lens fluorite + total length, correction of chromatic aberration is easy
  • In short lens fluorite + total length, correction of chromatic aberration is difficult
  • Diffractive optical element (DOE)
  • Diffractive optical element can be corrected if the chromatic aberration
  • Flare caused by light diffraction

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