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White Balance on HDX-900
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[Charles Boileau] “by Charles Boileau on Oct 22, 2008 at 7:37:34 am
Did you do those tests in the same lighting condition? Meaning: Did you have the same amount of light?”
Charles, I’m sorry, but I don’t really understand your question. Properly exposed is properly exposed, but yes, the light levels were similar, with adjustment made by using the camera iris.
What I don’t understand is how the light level is relevant to the issue if the exposure is the same.
Are you concerned that my test is flawed? I wasn’t trying to prove a point with the test, only to see what the best settings on the camera are.
Let me add one more thing: Noise is not the crucial issue here. By understanding the native white balance of the camera one can avoid color shifts in the highlights when using FilmRec mode in the Varicam, or when using aggressive knee settings in the HDX900 (or even a Sony f-900).
When shooting with a large knee adjustment, it’s possible for one of the color channels to clip before another. When this happens, there will be a color shift in the highlights. The Sony camera tries to fix this by having a color control in the menu for parts of the image effected by the knee control. There is no such adjustment in the Panasonic cameras. Using a setting that requires the least electronic adjustment for white balance minimizes this risk. I have determined that the Varicam is more closely balanced to daylight than tungsten light.
We will always have to use some electronic adjustment to the native white balance unless you want to make a custom set of filters to change daylight and tungsten light to something like 4700k and to enter custom RGB gain adjustments in the camera to set everything straight. Not a very practical solution in my opinion.
Varicam/Steadicam Owner
Los Angeles, CA
http://www.brucealangreene.com -
Thanks for all the info. It seems I didn’t understand your first explanation.
What I meant is that some cameras tend to be very noisy in darker areas. Which might of been an issue in your test.
Thanks again!
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[Charles Boileau] “Re: White Balance on HDX-900
by Charles Boileau on Oct 22, 2008 at 11:13:30 amThanks for all the info. It seems I didn’t understand your first explanation.
What I meant is that some cameras tend to be very noisy in darker areas. Which might of been an issue in your test.
Thanks again!
“I did observe that the Varicam is less noisy in the darker areas when electronically set for daylight than when set for tungsten. I guess that should be true for the 900 as well since I think it uses the same chip assembly.
Varicam/Steadicam Owner
Los Angeles, CA
http://www.brucealangreene.com -
Maybe this will explain it better.
https://en.wikipedia.org/wiki/Color_temperature
Ernie Santella
Santella Productions Inc.
http://www.santellaproductions.com -
Your posts,Bruce have been very helpful in getting a better understanding of white balance within the menu system of the HDX900. Lets say for instance that I show a white balance of 3000k in the viewfinder. When I electronically change that to read 3200k and above the image is warmer. That’s opposite of what I thought it would be…the higher the kelvin temp the cooler the image. Could you explain the logic that I’m missing?
Thanks!Mark D
Mark D’Agostino
http://www.synergeticproductions.com -
Sorry, no disrespect on your experience. I think I understand. IF you dial the camera down to 3000k then you are correct, it will look cooler. The reason is, the physical light is at 3200 and the camera is now 3000k, so the light will be higher, thus bluer.
There are other options like getting a set of Warm cards.
Ernie Santella
Santella Productions Inc.
http://www.santellaproductions.com -
Ernie,
Thanks for such a quick response. I do understand the mathematics of white balance as I’ve been doing this since the image orthicon tube days. I was just wondering how to interpret the 900’s readout. When I white balance and it reads 3200K under tungsten light that’s basically fine. If I wish to warm that I’d typically add a fraction of CTO to bring it down to say, 3000k. If I wish to do something similar electronically, (oops, forget my gels), then my gut would be after white balancing to 3200k to dial down to 3000k in the menu. However, that corrects in the “cool” direction. That’s the logic I’m fighting.Mark D’Agostino
http://www.synergeticproductions.com -
Ernie,
No disrespect taken. My question didn’t exactly demonstrate my experience, (2″quad to 16, 35 and HD over 30 years).
I have a set of blue cards and I use them quite often. Your explanation in this post was the one that finally clicked. Incredibly basic but my brain freeze got in the way. Thanks a bunch!Mark D’Agostino
http://www.synergeticproductions.com -
[Mark D’Agostino] “Ernie,
No disrespect taken. My question didn’t exactly demonstrate my experience, (2″quad to 16, 35 and HD over 30 years).
I have a set of blue cards and I use them quite often. Your explanation in this post was the one that finally clicked. Incredibly basic but my brain freeze got in the way. Thanks a bunch!Mark D’Agostino
http://www.synergeticproductions.com
“Mark, I don’t know the 900 camera menus, but I usually set my camera to daylight or tungsten preset and adjust the rgb gain controls to set the color balance. This makes it easy to return to the same settings if I need to duplicate the exact look in the future. By using the auto white balance the camera sets the rgb gain so that red=green=blue based upon the “white” card one sets it on and I find it difficult to set this as consistently and I don’t always want r=g=b and I don’t always carry a bunch of colored cards…Just thought you might want to try this approach if the 900 camera menu allows it.
-bruce
Varicam/Steadicam Owner
Los Angeles, CA
http://www.brucealangreene.com -
The 900 has a “rb gain”, (no “g”, which I like to leave alone anyhow). I have played with that. Using a chart and a vectorscope are fine if you’re just setting r=g=b, but I usually end up tweaking away from the “normal” balance using tinted cards. I like your approach. Are you painting this by eye?
Mark D’Agostino
http://www.synergeticproductions.com
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