An illustrated chronological story about how Canon autofocus systems and viewfinders went from a single AF point (1987) to 191 AF points (2020).
The number of AF points was increased, resulting in a 65-point AF system.
Each AF sensor is indicated with small rectangular frames. AF points are arranged in three large zones. As this system is installed in an APS-C camera, viewfinder coverage is pretty impressive.
The sensor uses the rectangular design that is covered in transparent optical polymer. One pair of detector lines in the center and the diagonal detectors use the dual-line zig zag detector layout to improve accuracy.
Depending on the lens attached to the camera, the number of usable AF points, AF point patterns or the types of AF sensors may vary.
If a lens with a maximum aperture of f/2.8 or faster is attached to the camera, all 65 AF points are standard-precision cross-type detectors, and the center AF point is also a high-precision dual cross-type detector.
When a lens having a maximum aperture of f/5.6 is used, all 65 AF points remain standard-precision cross-type detectors but the high-precision dual cross-type detector at the center turns into a regular standard-precision cross-type detector.
For the center AF point, standard-precision cross-type AF detection is even possible with lens and extender combinations having an effective maximum aperture as small as f/8. In addition, four AF points adjacent to the center AF point do also work at an effective maximum aperture of f/8. The two AF points to the left and right of the center are standard-precision vertical detectors and the two AF points above and below the center are standard-precision horizontal detectors. Autofocus is not possible during viewfinder shooting with effective maximum apertures slower than f/8.
The system has an AF working range of EV -3 - 18 (with the center AF point supporting f/2.8) at ISO 100.