Do not shoot auto - the shutter speeds will be too high in bright light. Learn best practice.
Normally, you want to shoot at double the frame rate. For 4K on the AX100, that means 1/60th shutter, fixed.
Why? too fast a shutter speed and you get jerky motion; too slow and the action will be too blurry. At 1/60th you get enough blur to smooth the action in video - blur is GOOD in video. Video is not just a sequence of stills.
This means the best way to shoot is to use shutter priority mode, setting the shutter at 1/60th.
The AX100 tends to overexpose; you must then set the dial in then front to "AE Shift". That way you can turn the dial to reduce exposure relative to what the camera will choose. You should use zebras (if you do not know what zebras are, you need to read) to tell you if there are large expanses of overexposure.
Shooting good video takes effort.
In bright sunlight, 1/60th shutter will result in very small apertures (and diffraction artifacts) or overexposure. The AX100 built-in ND filters must be used. Set them to manual
, and the camera amazingly will suggest to you which ND setting to use. Follow that advice. ND auto actually reduces options for ND filter use.
Shutter-priority, AE shift, manual use of ND filters are the key points in using the AX100. Do not use full auto mode.
Here two videos that used all the techniques:
And a frame grab from the above: