2014 will see the replacement of the Canon EF 100-400 f/4.5-5.6L IS, and we should see some new new patents showing new optical formulas for its replacement. Below is a patent for an EF 70-400 f/4.5-5.6L IS.

Description and self-interpretation of the patent literature

  • Patent Publication No. 2014-21256,2014-21257
    • Publication date 2014.2.3
    • Filing date 2012.7.18
  • Example 2
    • Zoom ratio 5.45
    • Focal length f = 71.33-144.71-388.95mm
    • Fno. 4.63-4.84-5.83
    • Half angle ω = 16.87-8.50-3.18 °
    • Image height Y = 21.64
    • 240.00-284.68-303.83mm overall length of the lens
    • BF 75.92-79.30-95.93mm
    • 6-group zoom of positive and negative positive and negative positive and negative
    • (Part of the fourth group) anti-vibration
    • Rear Focus (Group 6)

Source: [EG]


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