topic EOS R6 Mark II - constantly changes ISO randomly & white balance periodically in EOS DSLR & Mirrorless Cameras

EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

fstopPhoto — Tue, 18 Mar 2025 12:09:43 GMT

I started using this camera last September (2024) and every single time I use it the ISO randomly changes on its own. I typically shoot all indoor, low light situations with ISO 3200 - 4000. Exposures will be fine the suddenly either dark or overexposed. The ISO might go down to 400 or 640 or up to 12,500 for no reason whatsoever. This happens multiple times a day, every single day I use it. I'm ready to throw it out.

I have turned the return to auto ISO off and this does absolutely nothing. It's driving me crazy! Nothing works to change this. I have set the ISO range to a low of 3200 and a high of 6400, which I don't want it to be that high but that's the only option, set the ISO to 3200 and it will still change ISO to AUTO or to any ISO between 3200 and 6400 for no reason.

I thought maybe my forearm is touching the screen and somehow changing the ISO, which is hard to believe, so I turn the camera off when walking. I can turn it back on and the ISO has changed from my original settings. I can shoot a series of photos and it changes ISO on the next photo.

I have reset the camera to factory settings. The firmware is up to date but I downloaded it again and reinstalled the most current firmware and it still does it.

This is absolutely insane and I can't figure out why it's happening or how to get it to stop.

Every once in a while the white balance will also change randomly but that has only happened a few times in the last 7 months of use, whereas the ISO changes every single day, multiple times a day.

Any suggestions or Canon employees who can help with this?

Thanks,

Dave

Re: R6 Mark II constantly changes ISO randomly & white balance periodically

Waddizzle — Tue, 18 Mar 2025 12:04:07 GMT

Pay attention to how you hold the camera between shots.

I used to have similar issues. I would seem to get random under/over exposures for no apparent reason. Like you, I had just bought a new camera. At some point it I noticed that it was not happening, anymore.

I never did figure out why it stopped with any certainty. All I know for sure is that I had begun using Back Button Focus. It gave my thumb something to do besides linger and wander around the back panel. I guess I was tapping [AE Lock] or something. I don’t know.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

LeeP — Tue, 18 Mar 2025 12:13:14 GMT

Although this is not directly related to the question above, the detents for the mode dial on my R100 are so soft that I can inadvertently change modes holding/picking up the camera. Sometimes the most simple explanation is something we overlook because we tell ourselves it can't be that simple. Given the buttons on the backside of Canon cameras, the notion of touching something is plausible. I too would feel a sense of rage at having a nice camera like an R6 and find it "possessed".

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

LeeP — Tue, 18 Mar 2025 12:24:16 GMT

Waddizzle's explanation is plausible and the likely source of the issue, but you can always send it in for a once over if your frustration is getting to the fist through drywall level. Doing so would either tell you that something is wrong--and potentially fixable--or that nothing is wrong and Waddizzle's explanation of inadvertently touching/bumping something is possible.

Although I have not seen it with my Canons, I have had other cameras that were sensitive to battery strength and in one case replacing the battery was the savior. I am NOT suggesting that you buy another battery to test out this theory, but if you have a back-up battery that you never use, charge it up and see what happens. This suggestion is pure spitballing rather than any empirical knowledge of the issue. Though I feel empathy for your predicament, I realize that does little to solve the issue.

If a solution doesn't come from this discussion, have it looked at. Good luck in your endeavor to solve this issue and keep us posted if you figure it out because it helps to know that too.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

p4pictures — Tue, 18 Mar 2025 12:29:09 GMT

Which shooting mode are you using, is it one of the custom modes C1/C2/C3?

With custom modes the setting for auto update stored settings is important. If set to disabled, then any changes made to the camera - ISO, custom functions, auto ISO range etc, are not saved. So when the camera switches off, or is switched off or the mode changed then the changes are lost.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

fstopPhoto — Tue, 18 Mar 2025 14:05:52 GMT

I shoot in manual mode 99% of the time. Last week I got so fed up with it that I set a custom mode and set a low ISO of 3200 and a high of 6400 and it still changed randomly.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

p4pictures — Tue, 18 Mar 2025 16:23:37 GMT

When you set the ISO range, did you do both the auto range and the manual chosen range?

From the EOS R6 Mark II ISO Speed setting menus, I see this on my camera when I set the ISO speed range to be from 3200-6400 as you described. This range setting only applies to ISO values chosen by the photographer. Since even with this range limitation the photographer can also choose AUTO ISO. In my second screen capture you can see exactly that.

However the range for AUTO ISO is determined by the AUTO range setting, and in my camera that is set for 100-25600. This means that if I choose auto ISO then the camera can work with any ISO between 100 and 25,600. IF you want to restrict AUTO ISO then you need to do the same 3200-6400 limitations as you do for the manually chosen ISO in the second line. The two are independent.

Additionally check what you have set in the camera custom functions for Speed from metering/ISO auto. When this is set to the default setting - Restore Auto after metering - then if the camera is set to AUTO ISO, you can turn the ISO dial and change ISO to a value in the 3200 - 6400 range.

However as shown below, there is a grey AUTO icon next to the ISO value, and this is to indicate that once the metering timer expires the camera will return from the current value to auto, which is what has happened in the last screen.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

fstopPhoto — Tue, 18 Mar 2025 18:55:15 GMT

I set all ISO ranges to the same thing. There is no option to not include Auto when setting speeds. Speed from metering is turned off.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

p4pictures — Wed, 19 Mar 2025 08:34:20 GMT

At this point I am somewhat at a loss as to how the camera is changing ISO beyond the ranges you specified. I have tried this with my own EOS R6 Mark II camera in both M, and a custom shooting mode configured with the same M mode and ISO settings, and there is no way for me to replicate your problem.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

fstopPhoto — Wed, 19 Mar 2025 19:20:30 GMT

Yet this is what mine does every single day, multiple times a day.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

mcoverton — Sat, 16 Aug 2025 22:37:12 GMT

Hey Dave,

I have been using my r6 mark ii for just over a month and thought I was going crazy. Mine is doing the exact same thing and I'm finding zero solutions. Were you ever able to figure out what the problem was?

Thanks,

Marianne

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

fstopPhoto — Mon, 18 Aug 2025 16:38:21 GMT

Sorry you're having the same issue. I sent my camera to CPS and they said they couldn't replicate the problem and sent it back. I got a survey and said I wasn't satisfied and got an email from a rep and after some back and forth I sent it back to CPS for repair. They still couldn't replicate the issue. Their "fix" was to set it to the LOCK feature which is useless because I'm always changing exposures and focus points. I'm ready to throw it away. I'd hate to sell it and stick someone else with the problem but at this point it's my only option. I don't even want to buy the same body again after this nonsense. I've been shooting professionally for 30 years and for 15 years before this. I know how to use cameras. I put my camera on a table after shooting and watched the ISO change from 3200 to AUTO on the screen without even touching the camera. I had it change ISO 3 times over 4 shots in 13 seconds. It went from 3200 to 4000 to 5000 while I was holding the camera up to my eye. I would contact CPS if you're a member or at least send it back telling them what's going on so they're aware of it because at some point they're going to have to figure this out. Another colleague of mine has the same issue but it doesn't seem to happen as often as I have it.

I typically shoot about 1,500 photos a day when I'm working and this happens multiple times per day. I told them to keep it as long as needed and to take as many photos as needed until they see it happen. They didn't do that.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

Waddizzle — Tue, 19 Aug 2025 00:20:27 GMT

“ I put my camera on a table after shooting and watched the ISO change from 3200 to AUTO on the screen without even touching the camera. “

That is normal behavior when the ISO is set to Auto. It switches when the metering timer expires.

As Brian pointed earlier, similar behavior can occur when using a custom shooting mode.

If you normally shoot with the rear display open, then I suggest you try closing it.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

fstopPhoto — Tue, 19 Aug 2025 13:20:31 GMT

Are you not paying attention here?? The problem is my ISO is NOT set to AUTO. I NEVER use AUTO ISO. I set the camera to a manual ISO, usually 3200 or 4000 since 99% of my work is indoors in low light meeting rooms. I have never set the camera to AUTO. The ISO still changes randomly. It's like the camera is always in AUTO ISO no matter what it's set on. I know how to use my camera. And the revert to Auto is turned off. There is no reason why the camera should change ISO from 3200 to 4000 to 5000 over 4 images taken in 13 seconds while not in AUTO ISO and the camera never left my eye and the lighting never changed. The camera is just f*cked up.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

JeffXB — Tue, 19 Aug 2025 14:20:13 GMT

“I sent my camera to CPS and they said they couldn't replicate the problem and sent it back.”

Perhaps you should try to document it. Maybe set up your camera and once it starts to act up use your cell phone to video the back panel display. Zoom in and also zoom out to show the camera is not being touched. I’d think that a few short video clips might help CPS figure out the issue, but I could be wrong.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

fstopPhoto — Tue, 19 Aug 2025 14:52:14 GMT

The main problem is that it happens while I'm shooting so it's impossible to document. It happens randomly. I would have to set the camera up on a tripod and just hope it happens. Over an 8 to 12 hour day and 1,500 photos taken it happens probably 10 times. Could be just a few times some days and more on other days. I have had the ISO set on manual 3200, turned the camera off and turned it back on to see an entirely different ISO. This forum and others have documented the same issue happening with the R6 and R6 Mark II. I'm not the only one. I just wish they'd get rid of Auto ISO in the first place. Who the hell uses that crap anyway?

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

Waddizzle — Tue, 19 Aug 2025 16:43:44 GMT

“ Are you not paying attention here?? The problem is my ISO is NOT set to AUTO. I NEVER use AUTO ISO. “

Of course, I am. What you described is how ISO Auto behaves. When metering is active, you will see an ISO value. When metering is idle, ISO will display Auto.

As I pointed out in the first reply, you could be brushing against the ISI control.

As Brian pointed out, even if you define a limited range of ISO values, the Auto option is always available. The Auto option will operate only within the range of ISO settings that you defined.

Which control do you use to set ISO?

Which control is configured for exposure compensation? This could explain outlier exposures.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

mcoverton — Tue, 19 Aug 2025 21:02:20 GMT

Well, darn. I'm finding several people that have had this exact issue and zero have found an answer. I think it's a faulty body and I'm so ticked. Mine does literally the exact same thing.

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

fstopPhoto — Tue, 19 Aug 2025 22:28:21 GMT

I'm not brushing up on the ISO control. You literally have to touch it at least 3 or 4 times to change the ISO. I thought that could be the reason when I first got the camera as I walked so I started turning the camera off as I walked. When I turn it back on it can be the same ISO or a totally different ISO. The ISO changes AS I SHOOT. THE CAMERA CAN BE UP TO MY EYE AND IT WILL CHANGE AS I SHOOT. That's not "brushing against the ISO control." The camera is just **bleep**ing trash. Everything I shoot is in MANUAL mode. I set the ISO, shutter speed, aperture, white balance - EVERYTHING. I don't use exposure compensation at all. I set the ISO with the touch screen at the bottom where the ISO is. You have to tap the ISO, change the ISO then hit SET. There's no way that's happening while the camera is up to my eye. Like I said, it will change ISO between turning off and back on.

This camera needs to get rid of the entire AUTO ISO feature all together. Who the hell uses that **bleep** anyway???? There is no option to turn AUTO ISO off on this piece of crap camera. It's always an option. I have set up Custom Modes and set an ISO range of 3200 to 6400 and it will still change ISO no matter what ISO I have chosen.

I just want AUTO ISO to GO AWAY COMPLETELY!!!

Re: EOS R6 Mark II - constantly changes ISO randomly & white balance periodically

fstopPhoto — Tue, 19 Aug 2025 22:30:29 GMT

Yeah, I think Canon has a piece of trash camera here and they refuse to acknowledge the problem. I'm seriously thinking about selling it, taking the loss and going back to my 5D Mark III.