AF Stop Button With the EOS 630/600, RT, A2/A2E/5, or 10 S /10 set to the AI Servo AF mode and continuous shooting, AF will not resume even after you let go of the AF stop button. Press the shutter release button halfway to resume AF.
Lenses that support changes in the AF speed Extender 1.4x EF-S 10-18mm f/4.5-5.6 IS STM EF- S 15-85mm f/3.5-5.6L IS USM EF-S 18-55mm f/3.5-5.6 IS STM EF-S 18-135mm f/3.5-5.6 IS STM EF-S 55-250mm f/4-5.6