Canon Patents Design for New RF Mount “Big White Zooms.”

With a new patent for an optical long-range zoom lens, Canon has done the math to create a larger, 200-500 F4/L IS 1.4x “big white lens” for the RF mount cameras.

The new lens isn’t just an EF lens with an RF mount modification either. It’s a seriously new way of looking down range.

In reality, the optical formula that is declared in the patent application, which was published on December 15, 2022, is not for one long-range zoom, but three.

Image Credit – Canon

Each with a similar design and a constant speed aperture, but with increasing focal length, all with a dedicated RF mount for Canon’s R-series mirrorless camera line, and a built-in extender.

Image Credit – Canon

The lenses are as follows:

Canon RF 200-400mm f/4L IS 1.4x

  • Focal length: 205.1mm – 385.5mm
  • F-number: 4.1
  • Half angle of view: 5.99 – 3.21
  • Image Height: 21.63mm
  • Length Overall: 367.62mm
  • Back Focus: 39.994mm

Canon RF 200-500mm f/4L IS 1.4x

  • Focal length: 207.0mm – 487.9mm
  • F-number: 4.1
  • Half angle of view: 5.97-2.54
  • Image Height: 21.63mm
  • Length Overall: 410.05mm
  • Back Focus: 39.998mm

Canon RF 300-700mm f/5.6L IS 1.4x

  • Focal length: 288.1mm – 678.9mm
  • F-number: 5.7
  • Half angle of view: 4.30-1.83
  • Image Height: 21.65mm
  • Length Overall: 410.05mm
  • Back Focus: 39.998mm

Though the focal length covers between 200-700mm in range, the application calls the optical formula for a “compact, high-performance zoom lens in which an extender group can be inserted.”

Canon has included the extender in the math that covers the optical alignment, and it is located on the image side of the stop for what Canon says is for the purpose of downsizing.

However, Canon says that the arrangement is specifically necessary for arranging the focus lens group on the object side of the diaphragm and to keep the lens small-sized, yet high-performance.

Mirrorless lenses are traditionally smaller than standard DSLR designs, and as such, the new optical formula may be necessary for keeping within the design spec of a more compact mirrorless design.

This is only a camera patent, however, and as such, there’s no specific lens announcement or rumor as to when this new optical scheme will hit the market.

But it does show that Canon is continuing to innovate, and it’s only a matter of time before we actually see it enter the market, and when it does, it’s probably best to start saving for it now because it won’t be cheap.

In the meantime, those big white DSLR lenses will have to use an EF-RF adapter in order to look that far down range.

[source: Canon Rumors, Asobinet]

  • Canon EF 200-400mm f/4L IS USM Extender 1.4x Lens (B&H)
  • Canon Control Ring Mount Adapter EF-EOS R (B&H)

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