Canon EOS REBEL T8i Advanced User's Manual page 364

External Microphone
If an external microphone equipped with a miniature stereo plug (3.5 mm diameter) is
connected to the camera's external microphone IN terminal, the external microphone will be
given the priority. Using a microphone such as Directional Stereo Microphone DM-E1 (sold
separately) is recommended.
Caution
Sounds from Wi-Fi operations may be captured with built-in or external
microphones. During sound recording, using the wireless communication function
is not recommended.
When connecting an external microphone to the camera, make sure the plug is
fully inserted.
The camera's built-in microphone will also record mechanical sounds of the lens or
sounds of camera/lens operations if AF operations are performed or the camera is
operated during movie recording. In this case, using an external microphone may
reduce these sounds. If the sounds are still distracting with an external microphone,
it may be more effective to remove the external microphone from the camera and
position it away from the camera and lens.
Do not connect anything other than an external microphone to the camera's
external microphone IN terminal.
Note
In Basic Zone modes, the settings available for [Sound recording] are [On] or
[Off]. Set to [On] for automatic adjustment of the recording level.
Audio is also output when the camera is connected to televisions via HDMI, except
when [Sound rec.] is set to [Disable].
The sound volume balance between L (left) and R (right) cannot be adjusted.
Sound is recorded at a 48 kHz/16-bit sampling rate.
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