Patent: Canon EF 400mm f/2.8L IS USM Lens with Built-in 1.4x and 1.7x Extender

The Current Canon EF 200-400mm f/4L IS USM Lens with Internal 1.4x Extender

Canon has filed a new patent for EF 400mm f/2.8L IS USM lens with built-in 1.4x and 1.7x extender. This patent showed that this new Canon EF 400mm f/2.8L IS USM lens has 2 stage built in extender (1.4x and 1.7x). So it means this new lens can reach a focal range of 400mm, 560mm & 680mm. The current Canon EF 200-400mm f/4L IS USM lens ($10,999 at Amazon, B&H, Adorama) with a built-in 1.4x extender can convert the focal range and maximum aperture to 280-560mm f/5.6.

Take a look at the patent details below translated by Google.

  • Patent publication number 2016-191761
    • Release date 2016.11.10
    • Application date 2015.3.31
  • Main lens
    • Focal distance 392.57
    • F number 2.90
    • Field of View 3.15
    • Image height 21.64
    • Lens total length 371.15
    • BF 44.00
  • Example 1
    • First state magnification 1.40
    • Second state magnification 1.70

Via: Egami

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