Council’s New Cameras
by Jason Fredin
Finally for the first time I feel actually qualified to talk about an issue facing council, the underexposure on the live stream when our mayor was on camera.
Before we talk about the small problem I want to say how terrific it is to have a live stream (and archive) of council’s meeting available. I also want to than Greg Fowler for leading the way, doing it independently which showed that it was possible and that there was a demand for it.
@cityofldnont Very dark when the camera is on the Mayor, as opposed to wood panelling behind C. White. Perhaps an on-camera light?
— Greg Fowler (@fowgre) October 31, 2012
I had noticed the exposure issue before Greg pointed it out but it was nice to hear that I wasn’t just being overly picky about camera settings.
The system is new and I’m not quite sure what capabilities the system the city is using has for adjusting exposure are, but I hope it gets straightened out soon.
For those of you a little more on the geek side…
The camera system council is using looks to be pretty advanced. Camera position and zoom are controlled by which council microphone is active. You can catch the camera moves as one speaker turns their mic off and another turns their’s on.
All this without the need for camera operators.
This is where the problem also lies. Without an operator (I assume and I may be completely wrong) focus and exposure have to be automatic.
The darkness is a result of the large white painted surface behind whoever sits in the mayor’s chair. This also is the case to a lesser extent with where Paul Hubert was sitting last night, all of them with those pesky white walls, Polhill and Usher looked great.
What caused that?
In an extremely simplified version the camera’s auto exposure looks at the scene and tries to make a guess at how bright to make everything, cameras have a pre-set neutral value, it has no idea what it is looking at though. Scenes that are predominately filled with light or dark colours cause problems.
Have you ever taken a picture outside in the winter of a snowy landscape and wondered why the snow looks grey or dark? It’s because the camera is attempting to reach an overall average grey. The old standard was what photographers call 18% grey.
So in our case the white wall behind Fontana causes underexposure (dark), the neutral wood wall behind Usher causes a proper exposure, while if a wall was painted black behind one of the speakers it would cause an over-exposure (bright). As a further example, I took frames from different positions into PhotoShop and blurred them to average their brightness and desaturated them to remove colour and you will notice they all turned out the same.
My first thought was exposure compensation, almost every camera has the ability to tell the camera not to use the default neutral value, but something brighter or darker. In this case it might fail though if there is not an adjustable level for each speaker location. Setting the compensation properly for Fontana and brightening the scene would cause the image to be over-exposed when the camera pans to Usher.
My second thought was manual exposure, something typically reserved for more advanced cameras where you remove the variable exposure system from the equation. All the speakers are similarly lit from the lights inside the room so their exposure values would be roughly the same. Problem being if there is any outside light chambers, or a light burns out, this would change the setting needed.
So what are we left with?
Either we paint all the walls in council chambers 18% grey, hope that the system has more advanced metering modes or features the ability to adjust exposure compensation individually for each position.