For the past couple of weeks I have been unable to change the ISO on my 1d Mark 111 to any setting lower than 200. I have tried everything I know and would greatly appreciate any ideas on how to get it back to normal.
I recently got the 5DMk2 and had the same problem. I had Highlight Tone Priority enabled which prevents the ISO setting from going lower than 200. If you have that function turn it off.
