BMPCC 6K and BMPCC 6K Pro White Balance Issue

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RoughEdit

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BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostFri Aug 12, 2022 6:16 pm

Is anyone else having an issue with the BMPCC 6K coming out much more warm in the white balance than the 6K Pro? I have them set to the same Kelvin and tint settings in each camera, but once I get the footage back to Resolve, its quite a bit different. Seems like the 6K is a bit warmer and a slight green tint compared to the 6K Pro. I've swapped the lenses too to make sure its not a color cast from there and I get the same results. Both are on Gen5 Color Science. Is there a calibration I should be doing with the 6K that I'm totally forgetting?

You can see the matching settings, plus the stills in the attached screenshot.
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carlomacchiavello

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostFri Aug 12, 2022 7:25 pm

Every sensor for the same camera is a bit different. Also if you try to pair Alexa and red you find a small difference between different camera.


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Pavel Lavrov

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostFri Aug 12, 2022 8:32 pm

You need to calibrate all lenses to reproduce colors exactly the same…

(not saying it can be done, just pointing at one more variable that hasn’t been mentioned yet)


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Robert Niessner

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostFri Aug 12, 2022 11:33 pm

I’d say the camera on the right with the wider lens is capturing a lot more of the reflected green light from outside’s greenery bouncing around. Don’t underestimate that.
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ShaheedMalik

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostSat Aug 13, 2022 2:04 am

The light looks different from the side in both shots. Just color correct in post.
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RoughEdit

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostMon Aug 15, 2022 1:16 am

Thanks for all the feedback everyone. Some extra context…

I tested that lens (Sigma Art 18-35) on both cameras and did get slightly different results, but not quite this different.

I was also using a Tiffen Vari-ND on the warmer shot here, and I have a feeling that might have been the culprit for the slight color cast this time. I’m going to do a few more tests and post the results.
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rick.lang

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostMon Aug 15, 2022 5:16 pm

Agree that a variable ND filter shouldn’t be used when you’re trying to compare the white balance between two cameras. It’s another point of uncertainty.

I’d recommend not using any filter at all in the comparison and just adjust shutter angle as needed rather than adjust the iris if needed to get a correct exposure.
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Uli Plank

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostTue Aug 16, 2022 7:11 am

Second that, keeping the iris constant. There are lenses that show different color casts when you change aperture considerably.
The software may be free, but the hardware needed for smooth performance is not.

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Robert Niessner

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostTue Aug 16, 2022 8:57 am

It is also important to point both cameras into the same direction onto your subject for testing purposes.
Otherwise all the stray light can lead to different outcomes. Basically in your examples above the sunlit plants outside act like a huge green screen and spill green color (and also some infrared) all over the room. While our eyes and brain will pretty much even that out, the cameras will react to this strongly.

For example during my live video days I had similar problems matching the cameras on large stages where the main lights had been tungsten and the at the back there were huge triangles of canvas back-lit by green LEDs. It was almost impossible to match the left, right and center cameras and I had to constantly tinker with the remote color controls when subjects were moving around the stage.
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wemrick1

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostTue Aug 16, 2022 11:35 am

I know you folks are shooting for clients and that makes this a problem. Personally, I like the difference as it lends to natural in the environment.
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Uli Plank

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostTue Aug 16, 2022 3:06 pm

Well, for the TO it is an issue.
The software may be free, but the hardware needed for smooth performance is not.

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wemrick1

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostTue Aug 16, 2022 6:30 pm

Uli Plank wrote:Well, for the TO it is an issue.

What is a TO?
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Uli Plank

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostTue Aug 16, 2022 7:07 pm

Thread Opener.
The software may be free, but the hardware needed for smooth performance is not.

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rick.lang

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Re: BMPCC 6K and BMPCC 6K Pro White Balance Issue

PostTue Aug 16, 2022 8:36 pm

AKA OP, original post.
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