1dxm2 - Telephoto Causing ISO changes in Manual Mode

[ctdennis11]

I've got a new 1DX Mark ii with a new EF 100-400 telephoto and am shooting in  manual mode. I set the ISO to 1000 (not auto) for example and as I zoom in/out I'm finding that the ISO changes. Is this expected behavior? How can I turn this off so that it remains constant? The behavior is causing some over exposure conditions.

[diverhank · Accepted solution]

You might want to check the menu and see if you have the option of safety shift Mode 2 turned on. If it's on turn it off

[ebiggs1]

Yeah, you set something wrong. Whether on purpose or by accident. Reset the camera in the menus under tools. Then spend some quality time with the 1DX Mk II manual.

[Waddizzle]

I think Safety Shift only applies to Av and Tv modes. Either you are in ISO Auto, or your fingers are hitting a button. You can test this last guess with the [LOCK] switch.

A custom shooting mode based upon M mode could cause this behavior, too. Settings can revert to default values if Auto Update is disabled.

[ctdennis11]

Thanks for the tips. It even changes in lock mode so something i've got set up in the infinite list of options is probably causing the problem. Will test and reply back.

[ctdennis11]

Safety switch mode was it. Thanks to all for the guidance!!