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ISO auto-changing / adjusting while in full manual mode on eos R




Recently my eos r has been changing the iso on me even after I change it back. The camera is in full manual mode. HOW DO I GET THIS TO STOP. I have the range set to 100 - 12800 (I'm going to lower it)  but I believe it's setting itself to even higher iso's despite this being the setting. 


Is this an error or is there some sort of ISO over-ride I'm not seeing here?


Product Expert
Product Expert

Hi lmetz,


Thanks for checking in with us.


The camera does have the safety shift feature which will adjust the ISO if the camera can't get a proper exposure. This feature is found in the Custom Functions menu, but it does not apply to the manual mode.


In the manual mode, I suggest that you double check the active ISO setting to make sure that AUTO ISO isn't active. Press M-Fn then turn the dial by the shutter to select a specific ISO level that isn't AUTO.


Thanks for your suggestion. Auto iso isn't active. I am manually changing iso and even hitting “lock” in hopes
of having it stay but it is still changing on its own. It is driving me CRAZY

"It is driving me CRAZY"


Well in my case it would be a short drive  Smiley Happy  but what you need to do first is reset your camera to defaults settings. Menus, tools, clear all settings and clear all custom settings. If that does not fix it and you have not gone crazy call Canon. 1 (800) 652-2666

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