Patent: Canon RF 300mm f/2.8L IS 1.4x plus other supertelephoto optical designs

Last updated: May 6, 2025 1:56 am

Published: October 4, 2022

1 Min Read

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One of the most popular, if not the most popular “big white lens” is the Canon 300mm f/2.8L IS. We're still waiting to learn more about an RF version of the lens. It's our understanding that Canon has done a complete ground-up redesign for the RF 300mm f/2.8L IS USM.

A new patent showing a bunch of super-telephoto optical designs has appeared, and all of these optical formulas come with a built-in 1.4x teleconverter.

We think that a 1.4x built-in teleconverter would be quite welcomed on an RF 300mm f/2.8L IS USM.

Canon RF 300mm f/2.8L IS USM 1.4x

Focal length: 300.00mm
F-number: 2.91
Half angle of view: 4.12°
Image height: 21.64mm
Overall length: 320.00mm
Back Focus: 49.68mm

There are also 400mm, 500mm, 600mm and 800mm optical formulas in this patent.

TAGGED:patent RF 300 f/2.8L IS RF 300 f/2.8L IS 1.4x

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ByCraig Blair

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.