Panasonic LUMIX S5 IIX - Shutter-Priority AE Mode

Metering / Exposure / ISO Sensitivity – Shutter-Priority AE Mode
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Shutter-Priority AE Mode
In [S] mode (Shutter-Priority AE mode), you can set the shutter speed
before recording.
The aperture value will be automatically set by the camera.
Slower shutter speeds
It becomes easier to capture motion
Faster shutter speeds
It becomes easier to freeze motion