EOS R5/EOS R6’s [Movie Servo AF speed] is settable when [AF: Movie Servo AF] is set to [Enable]. Additionally, this function is only enabled when using the following lenses compatible with slow focus transition during movie shooting. (USM lenses released in 2009 or later and STM lenses are compatible with this function.)

RF35mm F1.8 MACRO IS STM

RF50mm F1.2 L USM

RF85mm F1.2 L USM

RF85mm F1.2 L USM DS

RF85mm F2 MACRO IS STM

RF600mm F11 IS STM

RF800mm F11 IS STM

RF15-35mm F2.8 L IS USM

RF24-70mm F2.8 L IS USM

RF24-105mm F4 L IS USM

RF24-240mm F4-6.3 IS USM

RF28-70mm F2 L USM

RF70-200mm F2.8 L IS USM

EF24mm f/2.8 IS USM

EF28mm f/2.8 IS USM

EF35mm f/1.4L II USM

EF35mm f/2 IS USM

EF40mm f/2.8 STM

EF50mm f/1.8 STM

EF85mm f/1.4L IS USM

EF100mm f/2.8L Macro IS USM

EF300mm f/2.8L IS II USM

EF400mm f/2.8L IS II USM

EF400mm f/2.8L IS III USM

EF400mm f/4 DO IS II USM

EF500mm f/4L IS II USM

EF600mm f/4L IS II USM

EF600mm f/4L IS III USM

EF8-15mm f/4L Fisheye USM

EF11-24mm f/4L USM

EF16-35mm f/2.8L III USM

EF16-35mm f/4L IS USM

EF24-105mm f/3.5-5.6 IS STM

EF24-105mm f/4L IS II USM

EF24-70mm f/2.8L II USM

EF24-70mm f/4L IS USM

EF70-200mm f/2.8L IS II USM

EF70-200mm f/2.8L IS III USM

EF70-200mm f/4L IS II USM

EF70-300mm f/4-5.6 IS II USM

EF70-300mm f/4-5.6L IS USM

EF100-400mm f/4.5-5.6L IS II USM

EF200-400mm f/4L IS USM Extender 1.4x

EF-S24mm f/2.8 STM

EF-S35mm f/2.8 Macro IS STM

EF-S10-18mm f/4.5-5.6 IS STM

EF-S15-85mm f/3.5-5.6 IS USM

EF-S18-55mm f/3.5-5.6 IS STM

EF-S18-55mm f/4-5.6 IS STM

EF-S18-135mm f/3.5-5.6 IS USM

EF-S18-135mm f/3.5-5.6 IS STM

EF-S55-250mm f/4-5.6 IS STM