Canon EOS-1D X Mark II DSLR Camera (Body Only) - Manual (Page 426)

3 Custom Function Settings
426
C.Fn2: Exposure
Safety shift C.Fn2
OFF: Disable
Tv/Av: Shutter speed/Aperture
Takes effect in the shutter-priority AE < s > and aperture-priority
AE < f > modes. If the subject brightness changes and the
standard exposure cannot be obtained within the autoexposure
range, the camera will automatically change the manually-selected
setting to obtain the standard exposure.
ISO: ISO speed
Works in the Program AE < d >, shutter-priority AE < s >, and
aperture-priority AE < f > modes. If the subject brightness
changes and the standard exposure cannot be obtained within the
autoexposure range, the camera will automatically change the
manually set ISO speed to obtain the standard exposure.
When [ ISO speed ] is set, safety shift will also work with AEB shooting in
the < a > mode.
Under [ z 2: ISO speed settings ], even if [ Range for stills ] or [ Min.
shutter spd. ] is changed from the default setting, safety shift will
override it if the standard exposure cannot be obtained.
The minimum and maximum ISO speeds of the safety shift using the ISO
speed will be determined by the [
Auto range ] setting (p.167). However, if
the manually set ISO speed exceeds the [ Auto range ], the safety shift
will take effect up or down to the manually set ISO speed.
Safety shift will take effect if necessary even when flash is used.
If [ ISO speed ] is set, the camera’s internal temperature is low, and the
safety shift sets the ISO speed to ISO 32000 or higher automatically, the
maximum continuous shooting speed will decrease (except when you use
AC Adapter Kit ACK-E4). For details, see page 148.