New patent reveals how the Canon EOS R3 eye-detection AF may work

Canon Eye Control AF
(Image credit: Japan Patent Office)

The Canon EOS R3 looks set to be one of the most eagerly anticipated Canon camera launches yet, and the latest snippet in a steady trickle of teasers, rumors, speculation and soundbites is this patent application by Canon.

Picked up on by Canon News, this patent shows how Canon might solve a tricky issue of integrating an eye-detect sensor into an electronic viewfinder without affecting the viewfinder image quality.

The idea behind eye detection AF is rather clever. The camera viewfinder has sensors to detect the direction of your eye's gaze and can then automatically shift the AF point to where you are looking.

This sounds like cutting edge technology, but it's been done before. The Canon EOS R5 film SLR had eye control autofocus, though the success rate was not exactly 100% and it did not become a mainstream technology at that time. Canon must feel the time is right to re-introduce it. We've already reported on the Canon EOS R3 Eye Control function, and this latest patent suggests how it might be implemented.

The issue for Canon's designers is to incorporate an eye direction sensor into the viewfinder without obstructing the EVF. Its solution seems to be a small prism that deflects the image on to a dedicated eye control sensor at the side of the panel.

• See Canon EOS R3 announced

(Image credit: Japan Patent Office)

Canon's patent applications do not name specific models and its exploded diagram shows the camera as a simplistic set of blocks. However, knowing the EOS R3 is on the way makes the timing of this latest patent application look significant.

Read more:

Canon EOS R3 – 5 things we don't know yet (and 5 things we do)
Best Canon cameras
Canon EOS R5 review
Canon EOS R6 review
Best professional cameras

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Rod Lawton

Rod is an independent photography journalist and editor, and a long-standing Digital Camera World contributor, having previously worked as DCW's Group Reviews editor. Before that he has been technique editor on N-Photo, Head of Testing for the photography division and Camera Channel editor on TechRadar, as well as contributing to many other publications. He has been writing about photography technique, photo editing and digital cameras since they first appeared, and before that began his career writing about film photography. He has used and reviewed practically every interchangeable lens camera launched in the past 20 years, from entry-level DSLRs to medium format cameras, together with lenses, tripods, gimbals, light meters, camera bags and more. Rod has his own camera gear blog at but also writes about photo-editing applications and techniques at