Canon EOS-1D X Mark III DSLR Camera (Body Only) - Manual (Page 177)

Minimum Shutter Speed for ISO Auto
To prevent shutter speeds from being set too low automatically, you can set the minimum
shutter speed for ISO Auto.
This is effective in <
> or < > mode when shooting subjects in motion with a wide-
angle lens, or when using a telephoto lens. It can also reduce camera shake and blurred
subjects.
1.
Select [Min. shutter spd.].
177