BMPCC 4K: 'True' dual native ISO?

Hi there,

BMD is promoting the new dual native ISO (400 + 3200) of the BMDPCC 4K. I'm asking myself wether the it is an actual physical dual ISO (like the RED cameras are promoting with their new Gemini or the Varicam). Or wether it is just a metadata / software dual ISO?

Anybody is having info regarding this?

Cheers

How should dual ISO in software work?
For dual ISO you need to have two separate gain circuits - that is the whole point of it.

to be honest: I'm not too familiar with the technical aspects. I just read about the RED Gemini having 'truly physical dual native ISO" instead of in the metadata:

"It should be stressed that this is not merely an adjustment to metadata for the raw recording. It is a direct, physical change to the way that the sensor is capturing light." Source: https://www.redsharknews.com/production ... -unleashed

This made me think if the BMPCC4K could be 'described' the same if that is known yet.

Cheers

Fair question, Janis. I believe it’s two discrete circuits as Robert mentioned. The BMD home page describes it as “dual gain ISO” and the product overview describes it as “dual native ISO.”

Note that if you need the full dynamic range, you’ll stay in the 400 native ISO band, but if low light is required, there’s a small reduction in dynamic range using the 3200 native ISO band.

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Rick, is it true then that this camera will perform best left at 400 iso?

There's about a stop more dynamic range in the 100-1000 circuit than the 1250-6400 circuit. Within each circuit, the dynamic range is the same, regardless of ISO setting.

However, in low light, you'll get much more usable dynamic range using the 1250-6400 circuit, because of the high noise levels and murky detail you'd encounter in the 100-1000 range.

It seems it is human nature to take something that is simple, and make it complicated!
Unlike a lot of cameras I have used, BMD Cameras are actually very simple to operate.
Cheers

Rick, is it true then that this camera will perform best left at 400 iso?

For general purposes that’s likely true, but “best” like beauty, is in the eye of the beholder. There may be times when you want to go to ISO 3200 when some loss in dynamic range is tolerable.

Within either 400/3200 range, the allocation of stops above/below middle grey varies and you my find you prefer shooting at ISO 200 or ISO 1600 for example. Depends upon the subject as well as your intentions which you prefer. No “best” solution as you find what you prefer I suspect. I recommend one start with ISO 400 and 3200 to get a good understanding of the sensor and grain, but it won’t be long before you try other values.

Lots of positive comments about ISO 1250 and negative comments about ISO 1000. Personally I don’t expect I would exceed ISO 6400 except to test. Then again remember the clips shot with the recent Supermoon...


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[Kristian Lam]

Yes, baby. It's true.

Just made a post:
viewtopic.php?f=2&t=93636

I'm a bit confused with those charts.
There a different ones around:

Chart 01:


Chart 02:



In this video they show the first chart - so it seems there have been changes since the release of the camera.

The camera is a dual, iso invariant Sensor, meaning you have basically, two native ISOs, 400 and 3200.
ISO 400 offers a little more dynamic range, but 1250 is where the high circuit cuts in, giving you better shadow details but less dynamic range in the highlights. If you are shooting raw, only 400 and 1250 actually change the sensor exposure. The other ISO settings only change the image brightness on the monitor and are metadata. Correctly exposure the sensor for these two settings and you should get good results.
Cheers

The camera is a dual, iso invariant Sensor, meaning you have basically, two native ISOs, 400 and 1250.
400 offers a little more dynamic range, 1250 better shadow details but less dynamic range. If you are shooting raw, only 400 and 1250 actually change the sensor exposure. The other ISO settings only change the image brightness on the monitor and are metadata. Correctly exposure the sensor for these two settings and you should get good results.
Cheers

Hi Denny, it might be a typo, the native ISOs are 400 and 3200, not 1250...

The camera is a dual, iso invariant Sensor, meaning you have basically, two native ISOs, 400 and 1250.
400 offers a little more dynamic range, 1250 better shadow details but less dynamic range. If you are shooting raw, only 400 and 1250 actually change the sensor exposure. The other ISO settings only change the image brightness on the monitor and are metadata. Correctly exposure the sensor for these two settings and you should get good results.
Cheers

...thank you Denny.
I suppose the second chart is the current one... it is the same as in the manual from may

Captain Hook said the first one was made in error so it was corrected with the second one.

Yes, baby. It's true.

Where’s the LIKE button ??

JB

Yes youlikeny, if you look at the chart, the high iso circuit kicks in at 1250, and 3200 is a sweet spot for balancing highlight and shadow detail that matches 400 exposure latitude, so you could call these the two native ISO settings. I might have used the wrong term when saying “native ISO”. Another balanced highlight and shadow exposure seems to be 800 and 6400, where highlight and shadow latitude almost equal. So the ISO value you end up using, is going to depend on what your subject/lighting is and the mood you want to create.
Cheers