Blackmagic Forum

I'm trying to calibrate the nodal offset of a camera tracker for virtual production using the Aximmetry camera calibrator. To get accurate results, I need to know the exact sensor size (well, the sensor size with regards to the displayed pixels, of course).

I'm shooting 8K 16:9. According to the specs on the BM12K, the sensor is 27.03mm x 14.25mm. I'm assuming that's at what would be 8K DCI full frame - which is 8192x4320 pixels. 8K 16:9 is then 7680x4320. So I'm assuming that the sides are being cropped and the full 14.25 height of the sensor is still being used. So my calculation is simply: (7680/8192)*27.03 for sensor width = 25.34mm.

My question is - are my assumptions correct about how the sensor is being used in 8K 16:9?

I ask because my calibration numbers (for the nodal offset) are way off - and I'm trying to figure out what the source of error might be.

Unfortunately VFX Camera Database (vfxcamdb .com) doesn't include the 12K...

Yes, you are correct, according to this site:

Format: 12K, 8K, 4K 16x9
Resolution: 11520x6480
Dimensions: 25.344mm (H) x14.256mm (V) x 29.078mm (diagonal)

LENS COVERAGE AND CAMERA COMPARISON TOOL

https://cvp.com/tools/cameralens

BTW, due to the recent devaluation of the pound, this British site is selling the URSA Mini Pro 12K for $5,829 USD, not $6,385 if bought in the U.S.

Great, thanks! I was looking for a site like this that included the 12K.

Here you got the data visual as well and can compare it: https://sensorsizes.com