Understand factors that affect auto focus speed - EOS 7D Mark II

Article ID: ART168794 | Date published: 10/27/2017 | Date last updated: 11/30/2017


Learn how lens choice and the auto focus control method affect auto focus speed.


Auto focus method

If the auto focus (AF) method is set to [  + Tracking], [FlexiZone - Multi], or [FlexiZone - Single] for Live View shooting or movie shooting, the auto focus control method (phase-difference detection with the image sensor or contrast detection) switches automatically depending on the lens used and functions selected. This can greatly affect the auto focus speed. Phase-difference detection generally allows for faster focusing.

Contrast detection

When using the magnified view for Live View or movie shooting, or when Full HD 59.94fps / 50.00fps is set, contrast detection AF is used. The camera may take longer to focus.

Phase difference detection

Certain lenses do not support the Dual Pixel CMOS AF system or extenders. Phase-difference detection is used to determine the lens drive direction, and then contrast-detection auto focus is used to focus. The camera may take longer to focus.

Additionally, if lenses that do not support the Dual Pixel CMOS AF system or extenders are used when the camera is set to Continuous AF or Movie Servo AF mode, phase-difference detection with the image sensor is used for AF control.

The following lenses do not support the Dual Pixel CMOS AF system (production has ended for all lenses listed):
  • EF35-105mm F3.5-4.5
  • EF35-70mm F3.5-4.5*
  • EF35-70mm F3.5-4.5A*
  • EF28-70mm F3.5-4.5*
  • EF28-70mm F3.5-4.5 II*
  • EF100-300mm F5.6L*
  • EF100-300mm F5.6*
  • EF70-210mm F4*
  • EF50-200mm F3.5-4.5L*
  • EF50-200mm F3.5-4.5*
  • EF35-135mm F3.5-4.5*
  • EF28-80mm F2.8-4L USM
  • EF1200mm F5.6L USM
  • EF600mm F4L USM
  • EF14mm F2.8L USM
  • EF20-35mm F2.8L*
  • EF80-200mm F2.8L*
  • EF100-200mm F4.5A*
  • EF35-80mm F4-5.6PZ*
  • EF35-80mm F4-5.6*
  • EF80-200mm F4.5-5.6*
  • EF100mm F2.8 Macro*
  • EF35-80mm F4-5.6 II*
  • EF35-80mm F4-5.6 III*
  • EF80-200mm F4.5-5.6 II*
  • EF28-80mm F3.5-5.6*
  • EF35-135mm F4-5.6 USM
  • EF100-300mm F4.5-5.6 USM
  • EF70-210mm F3.5-4.5 USM
  • EF35-105mm F4.5-5.6*
  • EF75-300mm F4-5.6*
  • EF400mm F2.8L USM*
  • EF28-80mm F3.5-5.6 USM
  • EF28-70mm F2.8L USM
  • EF28-105mm F3.5-4.5 USM*
  • EF17-35mm F2.8L USM
  • EF24-85mm F3.5-4.5 USM
  • EF500mm F4.5L USM
  • EF24mm F1.4L USM
  • EF35-80mm F4-5.6 USM*
  • EF80-200mm F4.5-5.6 USM*
  • EF35-105mm F4.5-5.6 USM*
  • EF28-80mm F3.5-5.6 II USM*
  • EF28-80mm F3.5-5.6 III USM*
  • EF28-80mm F3.5-5.6 IV USM*
  • EF28-80mm F3.5-5.6 V USM*
  • EF28-80mm F3.5-5.6 II*
  • EF28-105mm F4-5.6 USM
  • EF28-105mm F4-5.6
  • EF90-300mm F4.5-5.6 USM*
  • EF90-300mm F4.5-5.6*
  • EF28-105mm F3.5-4.5 II USM
  • EF16-35mm F2.8L USM
Lenses marked with "*" have difficulties with Contrast AF and it may take a longer time to focus or the camera may not be able to focus.

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