topic Re: R5 Auto ISO - a bug or intended behavior? in EOS DSLR & Mirrorless Cameras

R5 Auto ISO - a bug or intended behavior?

Cytography — Thu, 29 Dec 2022 16:02:33 GMT

I just discovered an interesting behavior with my new R5 related to AUTO ISO. For sake of discussion, assume I’m in Av mode (haven’t tested this behavior in other modes). Using the Quick Control Dial #2 (the thumb wheel surrounding the Mode button), the default behavior is for that control to allow adjusting ISO. But, quite by accident, I discovered that if I use that dial to set ISO to something other than AUTO and then engage metering (either with half shutter press or back button focus) then I can’t set ISO back to AUTO for some number of seconds. This is true whether or not I take a picture.

The amount of time I must wait to be able to go back to AUTO ISO (using the control dial #2) seems to be tied to tied to the time set in “metering timer” on camera (red) tab 7. However, if I go into the menu at Camera (Red) tab 2 >> ISO settings I can override this time delay and immediately put the camera back to Auto ISO.

This behavior is different than my 5D Mark IV. On that Camera, regardless of how I have the metering timer set, I can always press the ISO button and turn the appropriate thumb wheel and immediately set ISO back to AUTO.

Is anyone else experiencing this seemingly unusual behavior? Is it possibly a bug, or might I have some setting somewhere set that is causing this behavior. I'm thinking possible bug since my 5D IV doesn't behave this way.

Re: R5 Auto ISO - a bug or intended behavior?

Waddizzle — Thu, 29 Dec 2022 16:47:32 GMT

Have you tested this behavior in other modes, yet?

I would also be curious to know the setting you are using for “Continuous AF” and “Safety Shift”.

Re: R5 Auto ISO - a bug or intended behavior?

Cytography — Thu, 29 Dec 2022 17:46:58 GMT

Same behavior in Tv and M modes. Continuous AF is disabled and Safety Shift is Off.

Re: R5 Auto ISO - a bug or intended behavior?

amfoto1 — Thu, 29 Dec 2022 18:14:53 GMT

I'm just guessing, but...

Do you have "AE-Lock" selected or enabled on the R5 and not on the 5DIV?

AE-Lock is used to take a meter reading and lock the exposure, then be free to recompose without changing those settings for a short period of time. I don't have either of those cameras, so don't know how long AE-Lock holds the settings after the metering, but seem to recall it's about 15 seconds on some Canon cameras I've used.

On many Canon cameras pressing the * button that temporarily activates AE-Lock.

But it is possible to set up the camera to always use AE-Lock, for every exposure. One way I recall was when setting up back button focusing on some cameras, one of the options is to use AE-Lock full time.

P.S. I have no idea why this started double spacing between lines or how to make it stop doing so. Sorry!

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2), EOS M5, some other cameras, various lenses & accessories
FLICKR

Re: R5 Auto ISO - a bug or intended behavior?

Cytography — Thu, 29 Dec 2022 18:18:41 GMT

That's a good question but, no, I'm not engaging :AE-lock. In fact I have the * (AE-Lock) button reassigned to be eye AF.

Re: R5 Auto ISO - a bug or intended behavior?

amfoto1 — Thu, 29 Dec 2022 19:44:27 GMT

Okay, you aren't manually selecting AE Lock and, in fact, have reassigned the asterisk button to other function...

Still, there are other ways that AE Lock can be activated. Next time you use your camera, look in the lower, left hand corner of the viewfinder. If you see the asterisk there, AE Lock is enabled. Why, I can't be sure... perhaps because of button reassignments you've made or something else changed in the menu.

I don't use AE Lock a lot myself. But I believe it can be cancelled manually by pressing the AF Point Selection button... So that's something else you can try, next time you see this situation with your camera.

***********

Alan Myers
San Jose, Calif., USA
"Walk softly and carry a big lens."
GEAR: 5DII, 7DII (x2), 7D(x2), EOS M5, some other cameras, various lenses & accessories
FLICKR

Re: R5 Auto ISO - a bug or intended behavior?

jaewoosong — Thu, 29 Dec 2022 19:51:40 GMT

I see the same behavior in AV mode. I've bumped that dial and switched to ISO 100 indoors once and wondered why my shutter speed was all of a sudden slow. Never had problems with my 5DmIV because that camera didn't have that dial. I debated disabling that particular dial but I just got used to checking for the auto iso if my shutter speed doesn't seem right.

Re: R5 Auto ISO - a bug or intended behavior?

Waddizzle — Thu, 29 Dec 2022 21:40:04 GMT

Another way to lock exposure is through locking an AF point prior to firing the shutter.

In One Shot AF mode, this means the exposure is locked when an AF point is locked. This is what “focus and recompose” was all about. A half-press should lock in the exposure until the metering timer expires, or if you release the half-press.

In Servo AF mode, the exposure is locked just prior to the shutter firing, which when you fully press the shutter button.

Re: R5 Auto ISO - a bug or intended behavior?

FloridaDrafter — Fri, 30 Dec 2022 00:28:57 GMT

@Cytography wrote:

Is anyone else experiencing this seemingly unusual behavior? Is it possibly a bug, or might I have some setting somewhere set that is causing this behavior. I'm thinking possible bug since my 5D IV doesn't behave this way.

Yes, it works that way on my R5 and R6. You don't have something set wrong, and our cameras are set up very modestly, so I can say that with confidence. I don't think it's a bug, but could be an oversight, however I do see the logic in the way it's tied to metering. It could just be the way MILC's work or a limitation although I don't see why.

We don't use auto ISO, but I just went through my books and the cameras looking for a solution. With metering tied to ISO, at this point, you just have one option, and that is to set the meter to four seconds and make do the best you can. I did find a menu where I think the option you want should be, and that is the third option in "Custom Functions Settings", menu one, "Speed from metering/ISO Auto". In that sub menu, you can set "Restore Auto after metering" or "Retain speed after metering". IMHO, there should be a "Restore Auto after shot" or something to that effect.

This might be a good one to submit to Canon Support as a request.

Newton

Re: R5 Auto ISO - a bug or intended behavior?

Cytography — Tue, 17 Jan 2023 14:43:47 GMT

Yes, I too haver concluded that this is "normal" as-designed behavior. It's not a huge deal, but I just find it odd that I can't over ride that delay and just instantly put the camera back into Auto ISO if I want to without the need to wait.

Re: R5 Auto ISO - a bug or intended behavior?

ForMatt — Fri, 25 Jul 2025 14:27:52 GMT

I can get my R5 back into Auto ISO immediately after double pressing the Mode button. Not ideal, but the quickest way I've found.

Re: R5 Auto ISO - a bug or intended behavior?

mrbuns — Tue, 14 Apr 2026 10:46:54 GMT

This is the best solution I have found on the whole internet for this issue. Did they change this behavior win a firmware update? I haven't updated mine in a while. Anyway, this reply should be pinned as the solution to the issue. It has been plaguing me for ages. Thanks

Re: R5 Auto ISO - a bug or intended behavior?

Waddizzle — Tue, 14 Apr 2026 18:31:07 GMT

“ This is the best solution I have found on the whole internet for this issue. Did they change this behavior win a firmware update? I haven't updated mine in a while. Anyway, this reply should be pinned as the solution to the issue. It has been plaguing me for ages. Thanks “

As near as I can tell, there isn’t any issue. It’s just the metering timer doing its job.

When yoi half press the shutter, the metering system wakes up, and the ISO display switches from AUTO to an actual value.

When the metering timer expires, the ISO display switches back to AUTO. If you try to change the value, the camera thinks you’re trying to override the Auto ISO values.

Re: R5 Auto ISO - a bug or intended behavior?

mrbuns — Tue, 14 Apr 2026 19:00:30 GMT

Yes, as has been mentioned several times already, this is "out of the box" intended behavior but that still doesn't disqualify it from being an issue, especially when other cameras like the 5Div don't do it a people get along with that system just fine. The issue also strikes in both directions; when in manual ISO mode and the shutter has been pressed (half or full) you also have to wait for the metering timer to end before you can scroll all the way back, past L, to put the camera in auto ISO again. This is a huge pain when you switch the camera on, fire off a few shots, and then you want to either switch to manual ISO or auto ISO without having to go into the menu or quick menu to do it, or wait for the metering timer to time out. The double press of the mode button is ideal

Re: R5 Auto ISO - a bug or intended behavior?

Waddizzle — Tue, 14 Apr 2026 20:22:23 GMT

“ Yes, as has been mentioned several times already, this is "out of the box" intended behavior but that still doesn't disqualify it from being an issue,….”

The cameras have been working this way for decades. I don’t”t think it is going to change anytime soon,

if you want to tweak the ISO on the fly when using ISO Auto in M mode, then I suggest programming the [Set] button for AEC,

Re: R5 Auto ISO - a bug or intended behavior?

mrbuns — Tue, 14 Apr 2026 20:32:02 GMT

I don't need it changed. As I said, ForMatt's solution is the best I have seen and probably better than anything that Canon would implement. I don't need to mess around with AEC, I have my solution right here. No more solutions, or assumptions, needed but thanks.

Re: R5 Auto ISO - a bug or intended behavior?

Waddizzle — Tue, 14 Apr 2026 21:33:53 GMT

I am still failing to understand the issue. The ISO mode remains in Auto the entire time, throughout the metering cycle. It switches between active and inactive.

If you have a solution, then please mark as the answer. Thanks, in advance.

Re: R5 Auto ISO - a bug or intended behavior?

mrbuns — Tue, 14 Apr 2026 21:47:53 GMT

If you don't understand the issue, or you don't encounter it yourself, that's fine but I don't really know why you would keep replying to this thread. Photographers use cameras in thousands of different ways so not everyone is going to encounter the same problems as others, and that's fine, but please stop adding to the thread. I didn't post the solution ForMatt did. Not only can I not mark my reply as a solution but there is already one, less helpful answer, tagged as the solution to this issue

Re: R5 Auto ISO - a bug or intended behavior?

Waddizzle — Tue, 14 Apr 2026 22:57:04 GMT

“ If you don't understand the issue, or you don't encounter it yourself, that's fine but I don't really know why you would keep replying to this thread. “

My mistake. I thought you were the OP. You’re not. I suggest that you start a new thread of your own. I promise not to reply to it.