I just read that the Canon EOS 5 had eye-controlled focussing. How does this work? In this short article I found that it had to do with the coupling of infrared eye-tracking and the AF-point choice, but it sounds a bit vague to me.

Could someone give a more detailed explanation?

  • \$\begingroup\$ interesting question, the past reserves a lot of surprises :-) \$\endgroup\$
    – Francesco
    Commented Jan 20, 2013 at 22:33
  • \$\begingroup\$ someone has been watching digital revolution ? \$\endgroup\$ Commented Jan 20, 2013 at 22:54
  • \$\begingroup\$ @Nippysaurus I have it from this. But I assume you mean the video that is linked there? Didn't watch it yet. \$\endgroup\$ Commented Jan 21, 2013 at 0:09
  • \$\begingroup\$ @BartArondson yep :) I watch all their videos and was also curious about the eye tracking. I thought he was joking at first. \$\endgroup\$ Commented Jan 21, 2013 at 1:15
  • \$\begingroup\$ I had this on Canon elan 2E worked great although that camera only had 3 focus points so it wasnt hard to tell which one to use. \$\endgroup\$
    – user32456
    Commented Sep 17, 2014 at 0:48

3 Answers 3


What is Eye-Control Focus(ECF)?

Through the tracking of eyeball movements, EOS cameras equipped with eye-controlled focusing (ECF) are able to choose the appropriate autofocus point based on where the user is looking in the viewfinder frame. (wikipedia)

How it works

More information can be found on the Photonotes.org Canon EOS Beginners’ FAQ Copyright © 2002-2013 NK Guy

A series of tiny infrared LEDs (light emitting diodes) shine harmless infrared energy onto your eyeball as you peer through the viewfinder. Light sensors record the infrared reflecting off your eye and calculate the focus point. A computer in the camera then examines this data and decides which of the focus points is closest to that point and selects it. If the camera is in AI Servo mode then it will also adjust focus automatically based on that selected point.


According to this page the camera employed infrared sensors to track eye movements and recognize which focus point had to be active.

This required a calibration with the eye: apparently 5 factory-made calibrations were available, and from the text of the page I infer that it was not possible to custom calibrate on one own's eye (don't know about the required accuracy, I guess that it also depends on the relative positioning of the AF points to discerne one from the other).


As an update, Eye Control AF has come back into the Canon lineup with the 2021 release of the EOS R3. Canon Asia describes how it works in this article:

Within the EOS R3’s electronic viewfinder, there are eight infrared LED lamps and a 7.56-megapixel line-of-sight detection sensor. The infrared LED lamps shine infrared lights onto your eye. The light that reflects off your cornea is picked up by the line-of-sight sensor, which uses the information to calculate where you are looking. Working together, they make high precision AF control possible with Eye Control AF.

The refinements here over the EOS 5's system is that instead of a single infrared sensor, on the R3 they're using eight different sensors at different angles to better accommodate different eye shapes and distances from the viewfinder. They have thousands of AF points to work with with entire sensor coverage. And there's extensive in-camera calibration on the R3 to refine the system for the individual user.

It apparently works pretty well. Dpreview has an article on the user experience of both calibrating and using the R3's Eye Control AF and it concluded with:

After this experience, I would frankly prefer not to use an AF joystick ever again. Even using a touchscreen just feels clunky after being able to take control over such a significant aspect of the camera simply by moving my eye. So while we're not sure that Eye Control AF is the single 'killer feature' that will sway people into buying an EOS R3, it is absolutely revelatory for some types of photography and in use, very quickly becomes second nature.


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