Why white balancing in your camera, may be a bad idea.

Postmaster

Postmaster

Dark Side of the Camera
I just have written an article on why white balancing in your camera, may be a bad idea.

I receive lot´s of questions on white balancing. Most people are staggered , when I tell them: “Don´t even think of touching that button”.

This tests where made with a HVX 200 under a 60 watt tungsten bulb. The results are similar in all video cameras, except maybe the ARRI Alexa, which has a surprisingly clean blue channel . Maybe ARRI is lowering the red gain instead of rising the blue, which would make much more sense (but that was only a prototype, so who knows).
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The full article here:

http://frankglencairn.wordpress.com/2010/07/23/why-white-balancing-in-your-camera-may-be-a-bad-idea/

Frank
 
Very interesting PostMaster. Makes sense to me. Thanks for the write-up. I would only consider this if I had a first pass one-light color grading option before sending the material to post. Otherwise, I'll get my WB in camera, so my intended look is more or less baked in from the start. I don't want to send an editor horribly balanced footage. Although you make a great case, many producers and others won't understand and it'd make me look bad! :)
 
I hate it to give away my footy without - at least - observing or supervising the grading.
Usually I do it my self, but I know, that´s not an option for everyone.

Frank
 
This was discussed at some length a few years back on the Panavision site. It really lent a lot of credence as to why shooting daylight, or HMI was a FAR better idea. Our cameras as a rule as STARVED for blue light. We have an abundance of green light which is why it's usually sampled twice as often in color subsampling routines. It's the cleanest channel by far nearly ll the time. White balancing in the camera typically just boosts the gain in the blue channel.


There is an exception to what you're saying here though. And that is you need to be careful if you don't white balance the camera to select a preset that is "close". You absolutely do NOT want to clip one of the other channels by not bringing them in line. If you are shooting in 2700K light and you are on a 6500K preset, you are going to be in major trouble.

This is another reason I tend to shoot somewhat flat in the camera. Adding gain to the color channels in post is a LOT less noisy. This can be overdone, but in general, I prefer to work that way.
 
Very nice Frank, thank you. I would much rather correct the footage in post, but have only been able to do that with footage I am shooting and posting. Down here is bottom feeder land, I rarely get an opportunity to supervise the grade on fictional narrative stuff I shot, so I usually end up being pretty anal about getting the white balance I want in camera. On the flip side I have also been pretty cavalier about really funking with WB, to get effects I want. I even WBed to the light of a dim pen light once to blow out the green of consumer fluorescents for a scene ( Morgue scene, Sorority girls vs. Zombies.... don't ask). I really thought that the in camera color would be cleaner then a post effect. I will really have to reconsider that now. Thanks again.
 
I hate to bump this thread, but I'm very much interested in this!

I guess my overall question is; generally, for daylight shots, what is the best white balance to use to get the least noise? I recently did a test shot in a forest during sunset (the only time that the forest didn't have such horrible variation between the shadows and sunspots) and while I didn't raise the ISO, I needed all the apeture I could get. With that being said, I did two videos, both the same, but different focuses. The one that had the blurred background, and focused foreground (a specific tree), the blurred background was so noisy it was pitiful, especially as the background trees got father away, and darker.

Yet, the video that had the background in focus, and the subject tree out of focus, there was literally no noise. I guess the details in the background 'broke up' the noise.

But I can't have that because the scene requires a out of focus background, yet I can't have the noise (and I have a T2i to make the tempeture settings tougher =/) I need some sort of setting to reduce that noise, it was severe and I don't know if the blues were too high or the reds were too high (I get alot of noise in the red channel for some reason, even in the most normal of conditions.) but something was off pretty severely. Pretty much like the difference between those photos on the website above.

So any suggestions on what to do with a camera that has no tempeture balance, just the built in white balances + white card manual? The T2i does have the white balance shift technology, but I don't think it can be applied on video (although if I knew which specific shifts corresponded with the 7D's tempeture settings, I could do something with that by taking the photos using the shift technology and using that as the manual preset for the video.)
 
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This is a great article and i do understand the science behind it...

The only thing that troubles me is that i was told constantly whilst in education that it is so important to get the correct WB and not to rely on the grade in post because you always loose something when adding something else...
I'd imagine you would need to use a well seasoned editor/grader to work with this footage after it has been shot at an 'incorrect WB'....?

As other people have mentioned, it is a 'risky' way to work... especially when working under producers and even editors that down really understand the in's and out's of it....

What would be peoples suggestions be if you are working in particularly warm situations like 2700k for example... but using a daylight WB....? That happened to me recently because i was shooting an event in a shop with large windows and the was a lot of DL but also there was large tungsten lights hanging and i did get very warm footage which didn't grade well... although i am by no means and editor/grader!! (ideally i should have 5600k geled the lights but time didn't allow)

Cheers

Tom
 
I have recently shot some vacation clips with the 550d and a rather cheap ND8 filter under strong sunlight, and I left the WB to auto, only to discover afterwards that I have the terrible magenta colour shift. I feel that this will be quite difficult to correct in post. Especially in frames where there are people, the skin has a terrible reddish color cast. I wish I had thought of white balancing my image before shooting. I think this would have made the color correction in post much easier and the footage much more useable.
I have decided to always keep a piece of white paper in my slingshot (and maybe to through in the garbage those ND8 filters after I'll be able to purchase something more decent)
 
kostas, with due respect, does frame-by-frame analysis of what you refer to as "vacation footage" really need that type of attention? it's a vacation video. it probably looks more badass than anything our parents though was cool. i'm just saying.
 
Snapper123 said:
I hate to bump this thread, but I'm very much interested in this!

I guess my overall question is; generally, for daylight shots, what is the best white balance to use to get the least noise? I recently did a test shot in a forest during sunset (the only time that the forest didn't have such horrible variation between the shadows and sunspots) and while I didn't raise the ISO, I needed all the apeture I could get. With that being said, I did two videos, both the same, but different focuses. The one that had the blurred background, and focused foreground (a specific tree), the blurred background was so noisy it was pitiful, especially as the background trees got father away, and darker.

Yet, the video that had the background in focus, and the subject tree out of focus, there was literally no noise. I guess the details in the background 'broke up' the noise.

But I can't have that because the scene requires a out of focus background, yet I can't have the noise (and I have a T2i to make the tempeture settings tougher =/) I need some sort of setting to reduce that noise, it was severe and I don't know if the blues were too high or the reds were too high (I get alot of noise in the red channel for some reason, even in the most normal of conditions.) but something was off pretty severely. Pretty much like the difference between those photos on the website above.

So any suggestions on what to do with a camera that has no tempeture balance, just the built in white balances + white card manual? The T2i does have the white balance shift technology, but I don't think it can be applied on video (although if I knew which specific shifts corresponded with the 7D's tempeture settings, I could do something with that by taking the photos using the shift technology and using that as the manual preset for the video.)
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Well, what WB setting did you have selected for the shots you describe? The T2i has multiple selectable WB settings, and you can set custom white balance with it. You said that you shot your scene at sunset. The light at sunset can be very difficult to get a good white balance with. The direct sunlight moves to much lower color temp the closer to sunset you get, and the reflected skylight can move higher. If you were on auto WB the camera could have struggled to get the WB right on those shots. The auto WB probably looks at the whole image and makes calculation as to the WB setting. Changing focus may affect that, and you had an issue like Frank describes, the blue channel gain was boosted to compensate for the mixed light.

The more I think about Franks suggestion the more I like it. The next project I am shooting I am going to have the luxury of being able to control the grading, so I am going to test staying with the 5600K WB setting, and correcting the WB in post, by manipulating the red channel, rather then the blue channel.
 
Chris Light said:
kostas, with due respect, does frame-by-frame analysis of what you refer to as "vacation footage" really need that type of attention? it's a vacation video. it probably looks more badass than anything our parents though was cool. i'm just saying.
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Of course this will never go on the big screen :-) (and I am probably wasting much time and sleep to cut and edit this) but I think even an untrained eye can see the strong reddish tint. I have not yet tried to correct the shots, but some stills shot with the nd filter are completely unuseable in my opinion.
I don't know if the filter is really that bad, but probably white balancing the image accordingly before shooting would have probably resulted in less pronounced effect...
 
While I very much agree with Frank, isnt colour temp/chroma level/phase another way of setting up the right colours before post production? I had a lot of problems mixing GH1 with HVX footage in post and found these settings to help a lot.
 
An easier way to go about would be when shooting indoors, CTB all the lighting (unless you want warmer areas - 1/2CTB) and then balance to 5600k... Then warm slightly in post if needed...?
 
finchy said:
An easier way to go about would be when shooting indoors, CTB all the lighting (unless you want warmer areas - 1/2CTB) and then balance to 5600k... Then warm slightly in post if needed...?
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Well, CTB has such a high filter factor that eats up a lot of light. The best way to go would to be use daylight sources, HMIs, fluorescents or CFLs and stay on the 5600K pre-set. However, Frank’s article does make a point about using the 5600K preset and still shooting under regular incandescent, and doing the WB in post. I am going to do some tests on that for sure.
 
David G. Smith said:
Well, CTB has such a high filter factor that eats up a lot of light. The best way to go would to be use daylight sources, HMIs, fluorescents or CFLs and stay on the 5600K pre-set. However, Frank’s article does make a point about using the 5600K preset and still shooting under regular incandescent, and doing the WB in post. I am going to do some tests on that for sure.
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Yeah thats the other option... Thats what i was getting at anyway!

I always feel that if you mess with colors in Post too much.. and try and make it look 'normal' then you can tell...i was always told that you can't do something without losing something else.. if you know what i mean. But maybe thats my low experience with grading.

I am all for not WB'ing though... the evidence speaks for itself so i will certainly stick with 5600k when i can!
 
There is a 2-1/2 stop difference between the red and blue channel under tungsten compared to daylight. If you want to avoid in camera blue channel noise shoot under the daylight balance selection as that is the native balance for all silicon based sensors. ( around 5500K color temp).

You can also use CTB filters either on lights or on the lens to correct, but you will give up 2 stops exposure sensitivity roughly.
 
no one ever mentions fitration on the lens

you can gel a load of lights or slip a simple blue filter on the lens

(blue coloured filter - ie lowers the levels of colours that are not blue)

Known in stills land as a tungsten correction filter

this will up the requirement for light but seems to me the way to go

shooting an daylight WB so no noisy blue amplification in camera, and you wont need to grade it so no noise creating blue amplification in post

you will need more light of course

of course daylight lights are best IMO


S
 
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