Canon EOS R50 Mirrorless Camera (White) - Manual (Page 149)

2.
Focus on the subject.
3.
Press the < > button ( ).
Center the subject on the screen, then press the < > button.
A preflash is fired by the flash, and the flash output required for
shooting is retained.
[ ] appears briefly on the screen, and [ ] is lit.
Each time you press the < > button, a preflash is fired, and the flash
output required for shooting is retained.
4.
Take the picture.
Compose the shot and press the shutter button completely.
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