Sony DSC-RX100M3 - Manual (Page 61)

When recording movies.
When using zoom functions other than the optical zoom.
When the shooting mode is set to something other than [Intelligent Auto] or [Superior
Auto], assign the [Zoom] function to the control ring before using the control ring.
[43] How to Use Using shooting functions Using the flash
Using flash
In dark environments, use the flash to light up the subject while shooting and to prevent
camera-shake. When shooting against the sun, use the flash to lighten the image of the
backlit subject.
1. Press the (Flash pop-up) slide switch to pop up the flash.
2. Press the shutter button fully down.
When you do not use the flash
When not using the flash, press it back into the camera body.
Note
If you fire the flash before the flash unit pops up entirely, it may cause malfunction.
You cannot use the flash when recording movies.