AF System

Speedy, Accurate Focus for any Scene

AF during viewfinder shooting employs phase-difference detection,which determines the distance to the subject instantaneously, thus allowing extremely quick focus establishment. An AF sensor is arrayed with a combination of line sensors with varying characteristics. For example, the f/5.6 line sensor, which operates when a lens with a maximum aperture brighter than f/5.6 is attached, is able to establish focus speedily from the defocused state. Meanwhile, the f/2.8 line sensor, which is activated when a lens with a maximum aperture of f/2.8 or brighter is attached, offers even a higher degree of focusing accuracy. Different line sensor combinations are used according to the characteristics of the respective models for enhanced AF performance.

AF Module of EOS 7D Mark II

Multiple AF Points and Cross-type Sensors

One of the advantages of the EOS system is the large number of AF points. There are 61 AF points on the EOS-1D X Mark II / EOS 5D Mark IV / 5DS / 5DS R, and 65 on the EOS 7D Mark II. Yet another distinctive feature of EOS DSLRs is the large number of cross-type sensors, which are made up of a combination of sensors for detecting vertical and horizontal lines, thus allowing accurate focusing without being subject to the shape and pattern of the subject. Many of the models are equipped with dual cross-type sensors to achieve a high level of AF accuracy by overlapping f/2.8 cross-type sensors at the frequently-used centre AF point.

Compatible Models: 1D X II, 5D IV, 5DS, 5DS R, 6D II, 7D II, 80D, 77D, 800D

61-point High-density Reticular AF Sensor on the EOS-1D X Mark II / EOS 5D Mark IV / 5DS / 5DS R

65-point All Cross-type AF Sensor on the EOS 7D Mark II

19-point All Cross-type AF Sensor on the EOS 750D

A: f/2.8 & f/5.6 Cross-type Sensor

B: f/4 Vertical Line Detection & f/5.6 Horizontal Line Detection Cross-type Sensor

C: f/5.6 Cross-type Sensor

D: f/5.6 Horizontal Line Detection Sensor

143-point: M50

65-point all cross-type: 7D II

61-point: 1D X II, 5D IV, 5DS, 5DS R

49-point: M6, M5, M100, M10

45-point all cross-type: 6D II, 80D, 77D, 800D

19-point all cross-type: 750D

9-point: 200D, 3000D, 1500D, 1300D


EOS iTR AF memorises the face and colour of the subject and carries out AF tracking through the coordination of the RGB metering sensor, which is able to capture viewfinder images as moving images, and the EOS iSA System, which performs sophisticated analysis of the subject. It provides support to AI Servo AF to further enhance the tracking performance. The EOS-1D X Mark II has a 360,000-pixel RGB+IR metering sensor, while that on the EOS 5DS/5DS R/7D Mark II is 150,000 pixels.

* iTR: Intelligent Tracking and Recognition

* iSA: Intelligent Subject Analysis

AF Compatible with f/8 Lenses

By combining the use of an extender with a super telephoto lens, cross-type AF by the centre AF point is possible up to a maximum aperture of f/8, allowing for the use of AF to capture scenes that frequently require the use of super telephoto lenses, such as sports, news coverage, and wild bird photography.

Compatible Models: 1D X II, 5D IV, 5DS, 5DS R, 6D II, 7D II, 80D, 77D, 800D

f/8 Lens Combination (Example)
EF 400mm f/4 DO IS II USM + Extender EF 2x III + EOS 7D Mark II

AF Configuration

AI Servo AF predicts the movement of the subject and maintains the focus on it. The method of prediction can be customized for models that come with the AF Configuration Tool. In addition to detailed settings such as subject-tracking sensitivity, acceleration / deceleration tracking, and AF point auto switching, you can also select the most suitable option from the six preset combinations depending on the type of sports activity you are photographing. The highly precise predictive performance ensures that you can track the movement of the subject during continuous shooting.

* The customisable items are different on the EOS 80D.


Compatible Models: 1D X II, 5D IV, 5DS, 5DS R, 6D II, 7D II, 80D

AF Microadjustment

This feature enables precise adjustment of the AF position, and provides support for fine-tuning of the focus required by professional users. For zoom lenses, adjustment can be made separately for the wide-angle and telephoto ends, and adjustment data for up to 40 lenses can be registered. As the lenses are identified using their serial number, you can also register different values for the same lens model.

AF Performance in Low-light Scenes

AF sensors require a certain amount of brightness to perform focusing. However, with the highly-sensitive AF sensors of EOS DSLRs, AF is possible even in a low-light scene where the subject cannot be identified with the naked eye. The centre AF point of the EOS-1D X Mark II / EOS 5D Mark IV / 6D Mark II / 7D Mark II supports up to EV-3, while that of the EOS 5DS / 5DS R supports up to EV-2.

* When a lens brighter than f/2.8 is attached.

Compatible Models: 1D X II, 5D IV, 5DS, 5DS R, 6D II, 7D II

Compatible Cameras