Canon EOS R5 C VR Creator Kit with RF 5.2mm f/2.8 Dual Fisheye Lens - Manual (Page 171)

Flash mode
You can select the flash mode to suit your desired flash photography.
[ E-TTL II flash metering ] is the standard mode of EL/EX series Speedlites for automatic
flash photography.
[ Manual flash ] is for setting the Speedlite's [ Flash output level ] yourself.
[ CSP ] (Continuous shooting priority mode) is available when using a compatible
Speedlite. This mode automatically reduces flash output by one stop and increases ISO
speed by one stop. Useful in continuous shooting, and helps conserve flash battery
power.
Regarding other flash modes, refer to the Instruction Manual of a Speedlite compatible
with the respective flash mode.
Caution
Adjust exposure compensation ( ) as needed in case of overexposure from flash
photography with [ CSP ] in [ ], [ ], or [ ] mode.
Note
With [ CSP ], ISO speed is automatically set to [ Auto ].
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