Page 1 of 1

Vectorscope Matching Issues on BMD Cameras

PostPosted: Thu Feb 07, 2019 6:12 pm
by Michael Lindblad
We have started to upgrade our studio and our productions to introduce more technical gear and attention to detail on all levels. This includes getting a Smartscope Duo 4k and a Flanders Scientific Monitor for coloring and scopes.
What we have noticed is we can not get any of our BMD Studio 4k Cameras or our URSA Broadcast to match our Colorchecker Video card to the vectorscopes 6 points (R,G,B,Yl,Cy,Mg) on either monitor.
We have tried up close and normal shooting distance, zoomed in full versus normal framing, Full studio Lights on versus few key/fill lights pointed at the card.
Is this a known issue on BMD cameras/ATEM Camera Control to struggle getting all 6 points to line up? Is there a detail we are missing or a technique we haven't tried yet? We are looking into LUTs for the URSA, but until we are uniform I need to be able to color and calibrate any and all cameras that come into our studio.

Current Gear and Testing Situation:
5x BMD Studio Camera 4k
3x Panasonic Lumix 35-100 Lens
2x Panasonic Lumix 14-140 Lens
1x BMD URSA Broadcast
1x Fujinon A20X8.6BRM: 20x 2/3 Lens
1x BMD Micro Studio 4k
1x Panasonic Lumix 14-42 Lens
Lighting with two Softboxes with light intensity at F2.8
Distance from chart range 14-18'
ATEM Camera Control Panel and ATEM Broadcast 4me 4K at 1080p 29.97
Scopes on Flanders Scientific CM171 (Calibrated in June'18 and Smartscope Duo 4K)

Re: Vectorscope Matching Issues on BMD Cameras

PostPosted: Thu Feb 07, 2019 7:50 pm
by Denny Smith
Try just shooting chart close up. A regular Color Checker is not going to line up, you need the special Cine/video model that has the RGB/Yl Cy Mg color tabs that align with the reference points on a Vectorscope. I also doubt you will ever get these cameras to hit all six targets. :roll:
Cheers

Re: Vectorscope Matching Issues on BMD Cameras

PostPosted: Fri Feb 08, 2019 5:06 am
by Andy Coulthurst
In my day ( BBC Studios ) we performed camera line-up using a uniformally illuminated standard luminance chart and adjusted colour levels such that black / white and intermediate levels had no cast.
Admittedly this is video/studio work in the mid 90’s. Is this no longer the accepted way to match cameras ?
It seems to me that unless you match intermediate points - you are most likely to have mismatches anywhere between the colour primaries/complements. The use of a vectorscope in this instance was only to ensure there was no colour cast ( use gain magnify and adjust colour balance to center the noise spot ).

If you check the link below and scroll down to colour balance
http://www.danalee.ca/ttt/appendices.htm

Re: Vectorscope Matching Issues on BMD Cameras

PostPosted: Fri Feb 08, 2019 6:33 pm
by Howard Roll
Those cameras are never going to hit all 6 targets, they only have primary color correction, RGB Gain/Gamma/Black. For any camera to hit all 6 targets they need to have secondary correction, in broadcast camera terms you're talking about the matrix, which is the relative value R-B, R-G, etc.,.

However it absolutely doesn't matter. The chart is also a new purchase? What you're seeing is perfectly natural for BM or any other camera. If every manufacturers camera hit the targets they would all look the same, get it? The deviation is the "look" of a given manufacturer.

If you can get them all white and gamma balanced you'll be fine. Matching each other is far more important than hitting targets on a card.

Good Luck

Re: Vectorscope Matching Issues on BMD Cameras

PostPosted: Wed Nov 13, 2019 4:04 pm
by Matt Penn
We've been using a DSC Labs Chroma DuMande chart and besides having to use a different Scope because BM doesn't have any Vector Gain control, we also noticed that the Ursa Mini Pro and Pro G2 color doesn't line up on the chart even with a normal 2X scope. What I understand is there is no Secondary Matrix adjustment in the Blackmagic Cameras, something that most other broadcast cameras do have.

Is this something that could be considered for the cameras / ATEM in the future?

Alternatively for now, in theory: Would I be able to take a sample of each camera and and do secondary color correction using our chart, and create a "Broadcast 709" LUT that I can load back in to each of the cameras that take the place of "Video Mode" that would give me a more uniform and matched color matrix?

Re: Vectorscope Matching Issues on BMD Cameras

PostPosted: Wed Nov 13, 2019 7:23 pm
by robertsmu
This video is the gold standard in color matching/balancing multiple cameras for broadcast. If you don't have a Tektronix waveform monitor with the diamond display, you can use the rgb parade view of other products, but it won't be as fast as Steve does here.

https://www.tek.com/how/camera-matching-alignment-video

Re: Vectorscope Matching Issues on BMD Cameras

PostPosted: Wed Nov 13, 2019 7:24 pm
by Howard Roll
I tried (everything) to create a simple 709 to 709 correction LUT under Resolve 14. Using the LUT function in both the Video Assist and in the Pix Monitor I could never get the generated LUT to work the same externally as it did in Resolve. Theoretically though it should be easy.