Canon EOS 250D Advanced User's Manual page 255

ISO Speed During Movie ShootingN
[ISO speed]
z
In manual exposure, you can set the ISO speed (= 222).
[Max for Auto]
z
You can set the maximum limit of the automatic ISO speed for ISO Auto
to ISO 6400 or ISO 12800.
Under [5: Custom Functions(C.Fn)], if [ISO expansion] is set to
[1:On], you can select [H(25600)].
Auto Slow ShutterN
[Disable]
z
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].
[Enable]
z
Enables you to shoot brighter movies, less affected by image noise,
than when set to [Disable] by automatically reducing the shutter speed
to 1/30 sec. (NTSC) or 1/25 sec. (PAL) under low light.
Setting to [Disable] is recommended when recording moving subjects under
z
low light, or when afterimages such as trails may occur.
You can set the ISO speed separately for
still photo shooting and movie shooting.
Set in [kISO speed settings] under the
[z] tab.
You can choose whether to shoot movies
that are brighter and less affected by
image noise than when set to [Disable]
by automatically slowing the shutter speed
under low light.
Applies when the frame rate of the movie
recording size is 8 or 7.
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