Color Temp/Color Phase vs. Warm card

PerroneFord

PerroneFord

Deals in Lead
Ok, here's one I haven't seen.

I have a need to shoot video in an environment that will tend to oversaturate the blue, and push the green levels. Clearly, I am going to need a way to shift the camera more red/magenta. My question is how.

My goal is to shoot as flat and noise free an image as possible. My master pedestal is set rather high (+10), chroma is already down as much as possible.

So the question is, which will produce an image with less noise? The warm card method, or the chroma phase/color temp? I am not necessarily trying to get ACCURATE color as much as I am trying to avoid clipping channels.

Thanks for any thoughts.
 
Great question. And - it's one I've been meaning to test myself.

I bought warm cards from Vortex Media a while ago and have not done a comparison versus in-camera. Hopefully, someone out there may have done this already. My hunch is that the warm cards will be 'cleaner'. Again - I don't know for certain. I've used all sorts of in-camera settings tweaks. I see considerable noise with even the slightest adjustments.

Let's get of the bottom of this...... Any and all input appreciated.
 
Agreed, hopefully someone out there has beaten us to this punch. Why do you suspect the warm card method will be cleaner? Do you think it's engaging some different circuitry than the color temp/chroma phase?
 
It doesn't really matter if you use the warm card or the color temp, they both affect the blue and red ADCs gain. Color temp is merely a more refined way of doing it. I recommend a gamma setting of LOW, a few of the gamma settings actually jack the RGB gain up, even if your master gain is set to 0 dB. You might want to look into some optical filters to help you out if your worried about massive channel clipping. Magenta and yellow combined will help you push down blue and green some.
 
By the way, if you see a clean image after a warm balance while shooting under tungsten, its because you are down playing the blue channels gain and jacking the red up, but tungsten is rich in red light....
 
Thanks CardMaverick. In my case, I do only custom scene files, so I won't be jacking up any RGB gain. My test fottage tonight looked pleasingly flat, but I'll be shooting some more tomorrow in full sun to see what I get.

Unfortunately, I won't be able to use optical filters, so I need to do as much in camera to get as soft (chroma wise) an image as I can.
 
PerroneFord said:
In my case, I do only custom scene files, so I won't be jacking up any RGB gain.
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Just be careful of the gamma and color temp settings though, which are under the scene file settings menu:

LOW, NORM, HIGH, B.PRESS, or CINE-LIKE are lower RGB gain settings.

CINE-LIKE_D or CINELIKE_V are higher RGB gain settings.

Color Temp adjustment lowers red and raises blue gain and vice versa.
 
Good to know.

I'll be using Norm. for my gamma settings, and I might shift the Color temp more red a bit since that is what I am looking for. Basically using that like the equivalent of a 1/4 red filter to suppress blue levels some.
 
cardmaverick said:
It doesn't really matter if you use the warm card or the color temp, they both affect the blue and red ADCs gain. Color temp is merely a more refined way of doing it.
Click to expand...

One would think. And that's been my assumption all along. I would still like to do some testing to see it firsthand. I'm not convinced that they would produce entirely the same results though. There's circuitry involved, whether you're dialing it in through scene settings or 'forcing' it on the camera with a white-balance fake. The proof would be in some screen grabs. I'd do it now but getting late....

Hence my question remains - anyone done comparison shots {color temp / phase vs. warm cards}?

Thanks in advance.
 
I'm going to be doing some shooting today. I'll see if I can't find some pastel blue paper to white balance with, and try a short test. The problem is finding something near me to shoot that show the color change critically. I don't have any charts or anything to shoot.
 
PerroneFord said:
My goal is to shoot as flat and noise free an image as possible. My master pedestal is set rather high (+10)
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Bad move. You want to go the other way if you want noise-free. Raising the master pedestal raises the noise noticeably. You should probably want to be down around -4 to -8 on a DVX, depending on which model.

Put the lens cap on, and turn the "marker" on. Then lower the master pedestal until 2 things happen: 1) the "marker" readout goes to 0%, and 2) the noise disappears. It's been a while since I've done this on a DVX, but on the HVX it happens at about -2 when using a video gamma.

So the question is, which will produce an image with less noise? The warm card method, or the chroma phase/color temp?
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Probably about the same; in both cases you're affecting the in-camera color balance.

Optical filtering might help a little, instead of trying to compensate digitally. Typically in a video camera you want to avoid gaining up the blue channel too much, which might mean you'd want to shoot under bluer light and white balance accordingly. At least, this works very well with the Red One.
 
Barry,

The idea here is to preserve as much information in the shadows as possible. I'll be dropping blacks in post. What has been happening is that the blacks have been getting crushed in the camera and losing all the shadow information. I have no intention of "finishing" the look in the camera.

Again, the optical filter may or may not be possible. I'll have to look into that. So the desire was just to work as much with the camera itself as possible.

Thanks for your thoughts.
 
Hey, have you tested the various color matrixes? Each one emphasizes different colors, and there may be one that emphasizes red/magenta over blue/green.
 
PerroneFord said:
The idea here is to preserve as much information in the shadows as possible.
Click to expand...
Well, that was part of your idea, but you also asked about lower noise. Raising the master pedestal = raising noise.

What has been happening is that the blacks have been getting crushed in the camera and losing all the shadow information.
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Again, cap the lens and look at the marker. If a pure black image is rendering at higher than 0%, that means you're not crushing anything. You haven't lost anything in-camera. If your blacks are raised above 0%, you're just throwing away dynamic range.
 
Barry_Green said:
Well, that was part of your idea, but you also asked about lower noise. Raising the master pedestal = raising noise.
Click to expand...

LOL! Sometimes you just have to spell it out for me Barry!


Barry_Green said:
Again, cap the lens and look at the marker. If a pure black image is rendering at higher than 0%, that means you're not crushing anything. You haven't lost anything in-camera. If your blacks are raised above 0%, you're just throwing away dynamic range.
Click to expand...

Done and got what I needed. Master Ped -2 for the for settings I had. Great tip and very simple.
 
Last edited:
Video on Vimeo of a sample.

http://www.vimeo.com/861347

Settings are shown on screen. In post, I increased contrast and saturate the colors to the level that I felt matched reality. Worked like a dream

Barry's tip will allow me more room in the signal to keep more whites.
 
AYes, I saw it. I didn't bother to pull it off for this test. Ordinarily it wouldn't be there, and any time I'd actually be using it, I'd be well zoomed in.

Good catch though! :)


Any comment on the levels? We shot this nearly at dusk with HEAVY cloud cover. The light was incredibly diffused so there were hardly any shadows to play with.
 
PerroneFord said:
Video on Vimeo of a sample.

http://www.vimeo.com/861347

Settings are shown on screen. In post, I increased contrast and saturate the colors to the level that I felt matched reality. Worked like a dream

Barry's tip will allow me more room in the signal to keep more whites.
Click to expand...

i went to think link at it stated "private clip" and won't allow me access.

huh?

what are the magic words which i can use to open the gate?

(i'm interested in the clip because i'm also interested in the effective use of vortex warm cards)

thanks in advance

be well

rob
 
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