Canon EOS-1D C - Manual (Page 21)

21
k Shooting Movies
ISO speed in the d, s, f, and BULB modes
The ISO speed will be set automatically within ISO 100 - 25600.
Under [z2: ISO speed settings], if [ISO speed range]’s
[Maximum] setting (zp.130) is set to [51200/H] in the d, s, and
BULB modes, the automatic ISO speed setting range’s maximum
will be expanded to H (equivalent to ISO 51200). Note that even if
you set [Maximum] to [51200], the maximum will remain at ISO
25600 and will not be expanded.
If [z2: Highlight tone priority] is set to [Enable] (zp.154), the
ISO speed will be ISO 200 - 25600.
Under [z2: ISO speed settings], [Auto ISO range] and [Min.
shutter spd.] cannot be set (zp.131, 132) for movie shooting.
Also, [ISO speed range] cannot be set in the s mode.
If [ISO speed range]’s [Minimum] is set to [L (50)] and you switch from still
photo shooting to movie shooting, the automatic ISO speed setting range’s
minimum for movie shooting will be ISO 100. It cannot be expanded to ISO 50.