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Canon Patent for EF-EF-M Adapter with Improved Auto-Focus Speed


Egami (translated) spotted what could be Canon’s best move to push their mirrorless cameras. A new EF-EF-M adapter that should deliver better AF speed when using EF and EF-S lenses. While the AF performance of Canon’s new EOS M3 is excellent with the native EF-M lenses, AF performance is limited when using EF lenses via the currently available adapter. If Canon puts such an adapter on the market it would a huge selling point for the EOS M3. Access to Canon’s extended lens lune-up, and same AF performance as with native lenses!

Machine translated patent description:

  • Patent Publication No. 2015-34903
    • Published 2015.2.19
    • Filing date 2013.8.9
  • Master lens
    • Zoom ratio 2.69
    • Focal length 72.13 135.02 193.99mm
    • Fno. 2.90
    • Half angle ω = 10.72 5.78 4.03 °
    • Image height Y = 13.66mm
    • Overall length of the lens 237.36mm
    • BF 54.00mm
  • Adapter installed
    • Zoom ratio 2.69
    • The focal length f = 72.12 135.00 193.96mm
    • Fno. 2.90
    • Half angle ω = 10.72 5.78 4.03 °
    • Image height Y = 13.66mm
    • Overall length of the lens 239.70mm
    • BF 16.77mm
  • Canon patent
    • Fast AF adapter
    • Wobbling corresponding
    • 3-group configuration of positive and negative positive
    • 2 group also serves as a focus group and the anti-vibration group
    • And realize high-speed AF focus group was lighter
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