A few questions, and some background for each.

I was thinking about this when replying to another topic, about how the 6K model has Native ISOs of 800 and 5000, while the the 8K model has Native ISOs of 800 and 4000.

1) Does this mean the 8K model is noisier in low-light situations than the 6K?

It's my understanding that a Native ISO is the voltage to the sensor that produces the lowest amount of noise.

So that also leads me into my next question:

2) Where on its ISO scale does the Ronin 4D 6K sensor switch from the voltage of 800 ISO to the voltage of 5000 ISO?

200

250

320

400

500

640

*800*

1000

1250

1600

2000

3200

4000

*5000*

6400

10000

12800

Another way of asking this question: Is 1000 ISO just 5000 ISO with the gain turned way down (applying negative gain to the signal)? Or is 1000 ISO the voltage of 800 ISO with gain applied?

If it's the latter, then I'd assume the Ronin 4D-6K uses the voltage for 800 ISO all the way up to 1600 ISO, and then switches to the voltage for 5000 ISO at 2000 ISO. But there is no evidence to this assumption, hence why I'm asking. I'd like to know for sure what DJI says.

Which leads me to my final question, which I believe other users here could answer as well:

3) In terms of noise reduction, is there any point to shooting at ISOs lower than 800?

Let's assume I can completely control the lighting on my set. So that if I want to shoot at 200 ISO instead of 800, I can always use brighter lights (even if I want to stop down or shoot at a higher shutter speed). Why would I bother? Will I see any real reduction in noise?

Thanks everyone, hope you're all having a wonderful week!

This is something I would like to know as well.

If it's not mentioned in the specs maybe you can dial from 800 ISO to a higher value step by step and see when the image is 'flashing' and shows less noise and worser highlights. That will be the point where the ISO switches from low to high.

Here's an explanation of dual ISO on the: Blackmagic Pocket 4K

Benno Z Posted at 2-2 03:08
If it's not mentioned in the specs maybe you can dial from 800 ISO to a higher value step by step and see when the image is 'flashing' and shows less noise and worser highlights. That will be the point where the ISO switches from low to high.

Here's an explanation of dual ISO on the: Blackmagic Pocket 4K

Thanks but I'd appreciate an official answer from DJI, rather than relying on experimentation alone.

Benno Z Posted at 2-2 03:08
If it's not mentioned in the specs maybe you can dial from 800 ISO to a higher value step by step and see when the image is 'flashing' and shows less noise and worser highlights. That will be the point where the ISO switches from low to high.

Here's an explanation of dual ISO on the: Blackmagic Pocket 4K

And to further clarify, because I don't want you to think I'm dismissing you:

I do know about how dual ISOs sensors work, in principle. And I've seen the tests that would seem to indicate that at least on other dual ISO sensors that lowering the ISO below the lower native value tends to decrease performance. (And I have seen claims that the sensor DJI uses for the Ronin 4D is the same sensor used in the Sony A7S III or IV.)

But how one engineering team uses a sensor VS how another team designs their camera's hardware, software, and signal path can be very different. They might use the same component, but implement it differently.

So that's why I'm looking for official word from DJI on how they use their ISO values, (and if there is any point to using 200 ISO when I can just get the same shot at 800 ISO with an ND filter engaged).