Canon R6 Keeps Changing Itself to Auto ISO

[DellaMorte]

I recently upgraded one camera from the Canon 5D Mark IV to an R6. I have noticed that during the reception while I'm using my Flashpoint (Godox) AD-200 strobes that my camera will not stay on manual ISO. After a few shots, the R6 keeps switching itself back to auto ISO. It is driving me batty. I've googled it and I'll I've found to do is limit my camera on how far of a range I will allow it to auto-adjust itself to. I haven't found a way to disable auto ISO altogether or found a reason as to why my camera keeps doing this.

My setup is the Canon R6 with the R2 Mark II ETTL Wireless Flash Trigger (with the newest firmware installed) and a Canon Speedlite 600 EX-RT on top. The trigger is controlling two AD200 with strobe head. 

The secondary problem I've been having is that while using this setup every now and then I'll take a photo and get a magenta cast.

[Waddizzle]

I do not own the R6.  But, the only time my [DSLR] camera settings revert to previous settings, or change on their own, is when I am using a custom shooting mode with the Auto Update feature disabled.

As far as images with a magenta [tint] go, I have seen that in JPGs when the WB is set for flash, and the flash does not fire at the correct time, or not at all.

[BeerBoy]

I own 3, r6 Bodies. All 3 of them do the same exact thing. I happen to know a video company who owns 12 of them, and the owner says all 12 of them do the exact same thing as the OP states, which is exactly what happens to me. I have a ridiculous amount of evidence that shows me clicking away with everything going normal, then without any warning whatsoever, the iso will jump from.. 100 to 1600 + + + + +++++ in the middle of a session..  and series of shots..

  Canon has not yet addressed this "Bug"..  with any firmware updates yet, and appears to have just written it off altogether!  Doesn't matter what iso it is set to... 100, 160..  400...  it will jump to 25000 or whatever, even IF outside in Sunny 16 lighting!! This flaw is ridiculous for the amount I and other have invested in the Canon Mirrorless system! Had I knows this before, I would have switched to Sony! 

[DellaMorte]

It still happens to me, I now own two R6 and kind of wish I would have waited for the second model. Canon just ignores so many things. I have two brand new batteries that are canon and made for that camera and I had to take them out of rotation because both cameras insist they are fake and will just freeze and shut off. I’m so far into canon I just have to wait it out I guess.

[p4pictures]

When the camera is set to auto ISO and you select ISO using the quick control dial you will notice that the selected value is shown, but next to it on the screen is the AUTO icon in grey not white. This is because the default behaviour for the EOS R6 and other EOS R-series cameras including the EOS R6 Mark II is to return from the selected ISO to auto after the metering timer runs out. 

Please also note that when the ISO is set to AUTO and flash is being used, the mirrorless R-series cameras vary  ISO much more than the DSLRs. DSLRs generally default to ISO 400 with flash and auto ISO, mirrorless the ISO will move between ISO 100 and ISO 6400 to suit the ambient light.

There is a setting on the camera in the custom settings to change this new ISO behaviour to the same as your older DSLRs. Navigate to Speed from metering/ISO Auto in the custom functions, then change it to Retain speed after metering. See the screens below, the screens are from EOS R6 Mark II, but the same setting on the first page of the custom functions exists on the EOS R6.