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.

[stevet1]

stokestack,

A couple of things:

1) Modern cameras are capable of handling higher ISO's than they used to.

2) For a fixed setting with constant lighting, using Manual Mode, where you dial in your settings yourself this will work just fine; but if you are in a setting where the light is constantly (and maybe quickly) changing, Manual Mode may actually work against you.

3) I could be wrong here, but on my camera at least, I'm pretty sure that when I use a semi-automatic mode, the camera sets a shutter speed that is twice the frame rate, i.e. at 30fps, it will set a shutter speed of 1/60th of a second. According to a lot of people, this the most natural flow of movement. Slower than that and you get fast, jerky movements. Faster than that and you get slow motion video.

If 1/60th risks overexposure, a lot of videographers will use a 3 stop ND filter to cut the light.

Steve Thomas

[stokestack]

Thanks for that, but it doesn't really have anything to do with the problem here. The whole point is to prevent the camera from changing the ISO (and the image quality).

As far as the shutter speed goes: You're pointing out another problem with this camera, which is the lack of a shutter-angle setting. In video mode, it shouldn't be referring to "shutter speed." When shooting video, it's customary to set a shutter "angle," which automatically changes with frame rate to ensure valid values. The term "angle" refers to circular mechanical shutters found on motion-picture cameras, where exposure time was determined by adjusting the size of a pie-shaped opening in the shutter disc.

And yes, the "normal" shutter angle is 180 degrees, which results in a shutter speed 1/2 the frame rate.

[stevet1]

stokess5ack,

Well, I guess the only way to prevent your camera from changing your ISO is to shoot in Manual Mode. (Unless your R6III behaves differently than my T8i).

Steve Thomas