Patent: Dual internal teleconverter telephoto lens.

Craig
1 Min Read

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Is this the next evolution of the Canon EF 200-400mm f/4L IS USM 1.4x? Here is a patent showing a dual teleconverter Canon telephoto prime, an EF 400mm f/5.6.

What's cool about the dual teleconverters, is one is a focal length reducer, so you get the EF 400mm f/5.6 and the built-in focal length reducer converter brings the lens to an EF 300mm f/4, or at the other end, a 560mm f/8 lens.

There has long been a desire for a replacement to the classic Canon EF 400mm f/5.6L, even if Canon just added image stabilization, but this is definitely a unique direction to take the lens on Canon's part.

Japan Patent Application 2019-70689 summary:

Canon EF 400mm f/5.6

  • Focal length: 391.89mm
  • F number: 5.80
  • Angle of view: 3.16°
  • Image height: 21.64mm
  • Total lens length: 299.31mm
  • BF: 167.00mm

With teleconvertor (B)

  • Focal length: 560.02mm
  • F number: 8.29
  • Angle of view: 2.21°
  • Image height: 21.64mm
  • Lens total length: 299.31mm
  • BF: 46.56mm

With Teleconvertor (C)

  • Focal length: 286.00mm
  • F-number: 4.23
  • Angle of view: 4.33°
  • Image height: 21.64mm
  • Total lens length: 299.30mm
  • BF: 110.04mm
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Craig is the founder and editorial director for Canon Rumors. He has been writing about all things Canon for more than 17 years. When he's not writing, you can find him shooting professional basketball and travelling the world looking for the next wildlife adventure. The Canon EOS R1 is his camera of choice.
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