Canon PowerShot SX70 HS Digital Camera - Manual (Page 120)

Using Auto Slow Shutter
Specify whether to reduce the shutter speed automatically under low light
when recording [
], [ ], [ ], or [ ] movies.
1
[ Auto slow shutter]
Enable
Enables you to record movies that are brighter and less
affected by image noise by automatically reducing the
shutter speed to 1/30 sec. under low light.
Disable
Enables you to record movies with smoother, more
natural movement, less affected by subject shake than
when set to [Enable]. Note that under low light, movies
may be darker than when set to [Enable].
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