Changing the ISO in CF on a 1D mkiii

[vandv61]

I have been unable to change the ISO in the CF menu to get it to go to 100 or lower The lowest it will go is ISO200 What am I not doing correctly? 

Thanks

[cicopo]

According to the manual for my Mark 4 (may be the same) is Cfun 1-3 and you have to choose Register & then APPLY whatever setting you REGISTER (if I'm reading the instruction correctly). I think you can choose more than 1 choice as the high & low limit

Just tried it out & I am reading it correctly. In Cfn 1-3 I have 3 choices, & if I choose Register I can then select the high limit on the first line, the low limit on the second line & then I had to select APPLY to lock them in.

[Ody]

Disable highlight tone priority.

[vandv61]

Thank You,  That did it, but why would that be set that way? and again thank you for your help

[cicopo]

Looks like the same thing is needed on the mark 4 for it to work too.

[diverhank]

I think it keeps ISO at 200 so the camera highlight tone priority function can play with the dynamic range by manipulating the ISO value below it.  If you shoot RAW, you can do it yourself post processing.  Having ISO stuck at 200 or higher is too limiting.