Canon EOS 77D Instruction Manual page 281

Focus and shoot the movie.
5
The procedure is the same as steps 3 and 4 for "Autoexposure

Shooting" (p.276).
ISO Speed During Manual Exposure Shooting
With [AUTO] (A), the ISO speed will be set automatically within ISO

100 - ISO 12800. The maximum limit varies depending on the
[kISO Auto] setting (p.320).
You can set the ISO speed manually within ISO 100 - ISO 12800 in

whole-stop increments. Under [54: Custom Functions(C.Fn)], if
you set [2: ISO expansion] to [1:On], the maximum limit of the
manual ISO speed setting range will be expanded so you can also
select H (equivalent to ISO 25600).
Under [54: Custom Functions(C.Fn)], if [4: Highlight tone

priority] is set to [1:Enable], the ISO speed will be ISO 200 - ISO
12800.
Since shooting a movie at ISO 25600 equivalent may result in much

noise, it is designated as an expanded ISO speed (displayed as "H").
When switching from still photo shooting to movie shooting, check the

camera settings again before shooting movies.
Changing the shutter speed or aperture during movie shooting is not

recommended since the changes in the exposure will be recorded.
When shooting a movie of a moving subject, a shutter speed of approx.

1/30 sec. to 1/125 sec. is recommended. The faster the shutter speed,
the less smooth the subject's movement will look.
If you change the shutter speed while shooting under fluorescent or LED

lighting, image flicker may be recorded.
If you set [s: Expo comp (hold btn, turn S)] with [14: Custom

Controls] under [54: Custom Functions(C.Fn)] (p.409), you can use
exposure compensation with ISO Auto set.
When ISO Auto is set, you can press the <A> button to lock the ISO

speed.
If you press the <A> button and recompose the shot, you can see the

exposure level difference on the exposure level indicator (p.282)
compared to when the <A> button is pressed.
By pressing the <B> button, you can display the histogram.

k Shooting Movies
281