Canon MV830 Instruction Manual page 48

Moving subjects may leave a trailing afterimage.
Picture quality may not be as good as in other modes.
White points may appear on the screen.
Autofocus may not work as well as in other modes. In such case, adjust the
focus manually.
Digital zoom and multi-image screen cannot be used while a night mode is
activated.
The program AE mode cannot be changed while a night mode is activated.
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