Ursa 12k Color Shift when shooting in 8k

I thought I was noticing a white balance shift when switching from 12k to 8k but I did some tests and it seems like it is mostly in the blue channel. It looks like when going from 12k to 8k (and 4k) you see some change in the blue channel like maybe some of the red channel is getting added into it.

Is this consistent with what other Ursa 12k cameras are doing? Maybe it is just a bug in the internal downscaling.

Here are some vectorscope images from Resolve. The red and green are also slightly different but Blue is definitely shifted to red/magenta.

8k Vectorscope

8K.jpg (98.6 KiB) Viewed 676 times

12k Vectorscope

12.jpg (98.75 KiB) Viewed 676 times

12k vs 8k Vectorscope

12k vs 8k.jpg (112.06 KiB) Viewed 676 times

Here are 2 frames if anyone wants to download and check my work.

https://elvisripley.synology.me:5001/sharing/gQxs4W5IT

I noticed this too, back when I got my 12k and did some initial tests. Going from 12k to 8k results in a overall cooler image and it stays the same in 4k. I think the camera boots into a different firmware when exiting 12k readout. For me I never felt like this is a problem as I rarely mix 12k and 8k footage, I usually decide beforehand what I want to shoot for a given project.

I might have to start doing that. I was doing some product shots at normal speed (12k) and then was doing some 120fps 8k so it became an issue.

There is a difference.

You’re using different parts of the sensor because of the way the photosites are arranged.

In 8k and 4k the pattern is the same. You’ll notice rolling shutter time changes between 12k and 8k but not 8k and 4k as well.

It shouldn’t be a huge difference though. If you’re seeing something that you consider unacceptable then you should reach out to BMD with examples and ask them to look at it.

JB