White balance

G

Greg Cokes

Member
Hello,

Will the White balancing procedure on the RED camera be the same as on any other video camera, IE via white cards?

I read somewhere that the Viper camera uses a black balancing system. If I understand it, it references black against the shutter when it is shut between frames. Is this correct or even possible?

Thanks,
Greg
 
I think a grey card would be better than a white card, as you don't want to white balance off a clipped signal.

In camera, there are a number of ways of setting white balance - via the grey card system mentioned above, and via dialing in the colour temperature of the light in degrees kelvin. This is great as you can add or subtract a few degrees to cool or warm up the image - no need for "warm cards".

Black balance is somthing different - it's to make sure that black is neutral, and yes, that's automatically handled in camera.

Graeme
 
Greg Cokes said:
Hello,

Will the White balancing procedure on the RED camera be the same as on any other video camera, IE via white cards?

I read somewhere that the Viper camera uses a black balancing system. If I understand it, it references black against the shutter when it is shut between frames. Is this correct or even possible?

Thanks,
Greg
Click to expand...

Both white balance and black balance are necessary in a video camera. it is the process of equalising the circuits inside the camera for the two colour extremes of no light and white light, white being whatever temperature you chose to call white. When the camera black balances it sets the offset of each colour channel to zero and when you white balance it sets the gain of each channel to be equal. So for whatever colour you have defined as white the red, green and blue will each give out an equal level.

Black balance is usually carried out automatically when you turn a camera on, but higher end cameras allow you to set black balance manually too because it can drift over time as the camera heats up. It isn't like white balance because you are always trying to achieve the same thing, zero output if there is no light input, that is why it is done automatically.

I would imagine the RED camera will allow you to white and black balance as normal for recording RGB. But there is another option which is much better. If you use Redcode Raw, you record the unbalanced Raw sensor data, that gives you the tremendous advantage of being able to do all your white balancing/colour correction in post. You will still need to stick a card in front of the camera as a reference though.

Martin
 
"when you white balance it sets the gain of each channel to be equal." - this is not strictly so. Perhaps it is in "video" cameras, but that's not how white balance really works in terms of colour science. Because it's a perceptual thing, you can't really do proper white balance in RGB, but you can in a perceptual spaced based around how the eye works. White balance then becomes a 3x3 matrix, rather than R,G,B gain values. End result is a much better image that you can set in degress kelvin quite nicely. That's how the current white balance in the REDCINE is working - you type in the colour temp of the scene, and bamm! you're balanced. Want it warmer or cooler, just add or subtract a few hundred kelvin.

Graeme
 
That is interesting Graeme. It makes me wonder if there are more profound tools for monitoring colour than vector scopes and histograms.

Martin
 
I don't think there are more profound tools in camera for this, but I guess it's good for readers to know the lengths we're going to with regards what you might consider a simple, well defined problem such as white balance.

Graeme
 
I don't think there are more profound tools in camera for this, but I guess it's good for readers to know the lengths we're going to with regards what you might consider a simple, well defined problem such as white balance.
Graeme
Click to expand...

We all know how hard team red is doing to please Graeme, thats why we are all believers and have reserved the red camera :)

Michael
 
Mike: Thanks. There's a lot of behind the scenes work on the camera by many many people that you just don't hear about. I'm lucky enough to be a public face, and to get to do some cool stuff too.

Graeme
 
Mike: Thanks. There's a lot of behind the scenes work on the camera by many many people that you just don't hear about. I'm lucky enough to be a public face, and to get to do some cool stuff too.

Graeme
Click to expand...

Like a lot of guys here on this forum i think it would be great if you guys could find the time to do a kinda video of progress through the development stage until completion. Now i dont necessarily mean the technical development but the "fun stage and laughs" maybe even the low stages as well "the break in" A video of Jarrad carrying all those boxes about and jarrad, Mike curtis Ted and Jim all looking at the footage for the first time. The comments regarding the red think tank and so forth. Maybe you could release it just as a memory for you guys and us here on the forum, lets not forget this camera is very very special indeed. Who knows we may look back on this as a true milestone in digital cinema.

Dont lose the opportunity even if it is a loose gathering of comments and guys all involved in the making of red one it would be interesting to see.

What do others think?
Michael
 
I know there has been a fair bit of documentation made during development. I don't know how much will ever see the public light of day though :-)

Graeme
 
Graeme_Nattress said:
Whisky of course! All I ever talk about are single malts, usually from Islay!

Graeme
Click to expand...

A touch of RED Label maybe

Caolila4.jpg
 
That'd be lovely. Don't think I can get that one here in Ottawa though. Just got a Glenfiddic 15, and a Laphraoig 10. Yummy.

Graeme
 
You must log in or register to reply here.
Back
Top