Canon EOS REBEL T6i Instruction Manual page 228

k Shooting Movies
Cautions for Movie Shooting
Do not point the camera toward an intense light source, such as the sun
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or an intense artificial light source. Doing so may damage the image
sensor or the camera's internal components.
If <Q> is set and the ISO speed or aperture changes during movie
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shooting, the white balance may also change.
If you shoot a movie under fluorescent or LED lighting, the movie may
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flicker.
Zooming the lens during movie shooting is not recommended. Zooming
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the lens can cause changes in the exposure regardless of whether the
lens's maximum aperture changes or not. Exposure changes may be
recorded as a result.
You cannot magnify the image during movie shooting.
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Be careful not to cover the built-in microphones (p.222) with your finger,
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etc.
General Movie Shooting Cautions are on pages 253-254.
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If necessary, also read the General Live View Shooting Cautions on
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pages 218-219.
Do not hold the camera in the same position for long periods of time.
Even if the camera does not feel too hot, prolonged contact with the same
body part may cause skin redness, blistering or low-temperature contact
burns. Using a tripod is recommended for people with circulation problems
or very sensitive skin, or when using the camera in very hot places.
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