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

What’s cool in regards to the twin teleconverters, is one is a focal size reducer, so that you get the EF 400mm f/5.6 and the built-in focal size reducer converter brings the lens to an EF 300mm f/4, or on the different finish, a 560mm f/8 lens.

There has lengthy been a need for a substitute to the basic Canon EF 400mm f/5.6L, even when Canon simply added picture stabilization, however that is undoubtedly a novel route to take the lens on Canon’s half.

Japan Patent Application 2019-70689 abstract:

Canon EF 400mm f/5.6

  • Focal size: 391.89mm 
  • F quantity: 5.80 
  • Angle of view: 3.16° 
  • Image top: 21.64mm
  • Total lens size: 299.31mm
  • BF: 167.00mm

With teleconvertor (B)

  • Focal size: 560.02mm
  • F quantity: 8.29   
  • Angle of view: 2.21°   
  • Image top: 21.64mm   
  • Lens complete size: 299.31mm   
  • BF: 46.56mm 

With Teleconvertor (C)

  • Focal size: 286.00mm   
  • F-number: 4.23   
  • Angle of view: 4.33°   
  • Image top: 21.64mm   
  • Total lens size: 299.30mm   
  • BF: 110.04mm