Canon EOS 5D MARK IV Instruction Manual page 355

4K movie shooting
Shooting 4K movies requires a high-performance card. For details
on card requirements for movie shooting, see "Cards that Can
Record Movies" on page 356.
Shooting 4K movies or High Frame Rate movies greatly increases
the processing load. Compared with normal movie shooting, the
camera's internal temperature may increase faster or may
become higher. If the red E icon appears during movie shooting,
it indicates that the card may be hot. Stop the movie shooting and
let the camera cool down before removing the card. (Do not
remove the card right away.)
From a 4K movie, you can select any desired frame to save it as
an approx. 8.8 megapixel (4096x2160) JPEG still image to the
card (p.427).
To obtain better performance with the card, formatting the card with the
camera before shooting movies is recommended (p.73).
Movie-recording coverage
The respective area of the image sensor shown below is used for 4K
movies and Full HD and HD movies.
L Full HD
wHD
3 Setting the Movie Recording Quality
H4K
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