How do you disable auto-ISO on R6 III in video mode?

[stokestack]

I can find no way to disable auto-ISO in dedicated-video mode on the R6 mark III. I've dug through every menu multiple times, and even assigned ISO-setting to the multi-function button in both stills and video mode. The documentation 

Pressing it in stills mode does indeed bring up the ISO-setting screen. But in video mode it does nothing. This seems like a bug. Before I return the camera, I'd like to exhaust all info sources. The documentation is garbage, the worst manual I've seen in decades.

[shadowsports]

Greetings, 

Try selecting Movie aperture priority.

Canon : Product Manual : EOS R6 Mark III : Movie Aperture-Priority AE https://share.google/sXyQbWY9rmtJOSnIA

[stevet1]

stokestack,

On my camera (a T8i), I can shoot video in either Manual Mode, or in one of the semi-automatic Modes. If I use Manual, I have control of all the settings: shutter speed, aperture and ISO.

If I use one of the semi- automatic Modes (TV, Av, or P), the camera defaults to the P, or Program Mode, and the camera chooses the settings, although I still might be able manually select a different ISO (I'll have check on that one).

Steve Thomas

[shadowsports]

Greetings ,

Thanks Steve, I should have mentioned that.

In manual mode you are responsible for shutter speed, aperture and ISO.

[stevet1]

stokestack,

I just tested it out, and when I am in one of the semi-automatic modes on my T8i, (Tv, Av, or P), the ISO function is not available to me.It defaults to Auto ISO and I can't change that.

I can only make changes to my ISO if I am Manual Mode.

Steve Thomas

[stokestack]

Thanks for taking the time to do that.

Wow. That's a major design blunder. If we can't prevent the camera from degrading image quality "automatically," without giving up all automatic modes, that's a deal-breaker and probably the last straw for Canon in my gear collection.

[stevet1]

stokestack,

I actually like taking videos in Av Mode. My camera quickly adjusts the exposure to match the lighting conditions as you move from shady conditions to brightly lit ones. I don't have stop and fiddle with the settings to get a good exposure.

And with Movie Servo, I don't have adjust the focus either. The camera focuses for me.

Steve Thomas

[Waddizzle]

The only time the camera overrides your ISO setting is to correct for an under/over exposure.

In stills mode the behavior is called Safety Shift. 

[stokestack]

Right, but according to your tests, you can't set the ISO in Av mode either. For video, I would want to use Tv mode, so motion is always rendered the same way. And you absolutely don't want your video quality fluctuating... and that means you don't want your ISO changing by itself.

[stokestack]

Yes, I'm aware of that. But forcing the user to accept fluctuating image quality is absurd. Cameras in Program mode normally adjust aperture and shutter speed as far as possible to meet the needs of the scene, and then warn you when they can't do so. Then you can decide to change ISO, change your lighting, change your lens, or whatever. Having auto-ISO is fine as an option, but totally unacceptable for those who need to maintain image quality.