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Author Topic: What is white balance and what's the correct way to use it?  (Read 20720 times)

NotABunny

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Re: What is white balance and what's the correct way to use it?
« Reply #30 on: November 05, 2012, 11:07:09 AM »

Has anybody tried using Expodisc? Apparently produces great results, but it is a bit expensive, though.

I remember I read somewhere that even though one can correct WB in post it sometimes leads to wrong colors afterwards. Like, changing WB in post doesn't treat all colors the same, for example blue becomes darker blue while red doesn't and I belive some cast was mentioned. Does anybody have an idea about this issue?

The camera's WB doesn't affect RAW images, so that's possible only if the camera outputs JEPG whose WB processing algorithm is "better" than that of computer processing software.

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Re: What is white balance and what's the correct way to use it?
« Reply #30 on: November 05, 2012, 11:07:09 AM »

mirekti

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Re: What is white balance and what's the correct way to use it?
« Reply #31 on: November 05, 2012, 11:49:57 AM »
The camera's WB doesn't affect RAW images, so that's possible only if the camera outputs JEPG whose WB processing algorithm is "better" than that of computer processing software.

But I read somwhere that cameras collect data for different channels RGB and than applies WB. Too technical for me so maybe I explained it wrong. However, some say that even though one can play with WB in post it is not as precise as one would hit it the very first time.

My idea of using expodisc was a bit different than suggested. I'd like to use it in a room with multiple sources so I woud just point at the scene not each source and help camere make a good balance. Does this make sense? 
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Quasimodo

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Re: What is white balance and what's the correct way to use it?
« Reply #32 on: November 05, 2012, 02:16:41 PM »
The camera's WB doesn't affect RAW images, so that's possible only if the camera outputs JEPG whose WB processing algorithm is "better" than that of computer processing software.

But I read somwhere that cameras collect data for different channels RGB and than applies WB. Too technical for me so maybe I explained it wrong. However, some say that even though one can play with WB in post it is not as precise as one would hit it the very first time.

My idea of using expodisc was a bit different than suggested. I'd like to use it in a room with multiple sources so I woud just point at the scene not each source and help camere make a good balance. Does this make sense?

Just my two cents:

I my mind it makes sense, whether you use a Lastolite, like shown over (could very well be better than expodisc, but bigger to carry around by the looks of it (it is not like you don't have enough to carry around if you're doing a shoot)). I have a warm expodisc and it works great. However when I have forgotten it, I have often just used a regular xerox paper (they are not perfect white), or a recycled napkin (brown/greyish) and it works great too. If anything goes wrong in your opinion, you can fix it in pp.

The way I do it (and I am not a professional in the sense that this is my main income), is that I put the expodisc on the lens and shoot at the person's face very close to get the best reading. If you are using strobes or Speedlights, you would want to have a remote trigger (ST-E2, or ST-E3 if you have the 600 RT EX, youngno, or Pocket wizard or whatever). The reason you would want a remote trigger is that if you use a 580 or 600 as a master it will (not sure if they can trigger without emitting light?) cast light when you are standing next to your subject to get a reading, and that will affect the reading in a wrong direction. If you have the remote, you put up the flashes where you want them, then trigger them while taking a reading next to the subject, and then put in the reading as your custom white balance. If you don't have a expodisc, lastolite, cube or whatever, try with a xerox paper. What I do is to turn of the AF on the lens, put the paper right next to their face, make sure the lens is out of focus, take a shot, and it immediatly becomes better than the AWB will give you in my experience.

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NotABunny

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Re: What is white balance and what's the correct way to use it?
« Reply #33 on: November 06, 2012, 07:33:40 AM »
The camera's WB doesn't affect RAW images, so that's possible only if the camera outputs JEPG whose WB processing algorithm is "better" than that of computer processing software.

But I read somwhere that cameras collect data for different channels RGB and than applies WB. Too technical for me so maybe I explained it wrong. However, some say that even though one can play with WB in post it is not as precise as one would hit it the very first time.

My idea of using expodisc was a bit different than suggested. I'd like to use it in a room with multiple sources so I woud just point at the scene not each source and help camere make a good balance. Does this make sense?

Sense it makes, it may also be good enough, but it's not going to properly fix the color balance. That's because color is not given by the object, but by the light that hits the object and is reflected by it. I know that people are taught that objects have color, but that's simply wrong. Light has color and objects reflect a part of the light spectrum, with various intensities. For instance, if you have what you think is a purely red object that's illuminated by purely blue light, you'll see the object appear black, that is, it absorbs the light. So what is the correct color of the object? The one you think it is.

In the case of multiple light sources, you get a varying mix of seriously weird colors (coming from light bulbs).


Details here: http://www.cambridgeincolour.com/tutorials/white-balance.htm

Also see there white the green-magenta correct is available:
Quote
white balance uses a second variable in addition to color temperature: the green-magenta shift. Adjusting the green-magenta shift is often unnecessary under ordinary daylight, however fluorescent and other artificial lighting may require significant green-magenta adjustments to the WB.

What is not clear from that phrase is that the correction is necessary because the color balance was affected more in those areas of the spectrum, so that needs to be compensated separately than the rest of the color balance. This still doesn't describe all the differences in color from what a human expects, but it makes things good enough.

Also note that since the light spectrum reflected by the objects is not what the camera sensor was designed for (which is likely to be D65), you'll loose a lot of tonal definition, so color corrections in those areas of the spectrum will produce seriously noisy results.

Things like white discs may be used with good results if the light is consistent, so will not need to change the WB for each shot. But if that white disc will produce photos with white walls and shirts but people with orange or green skin, you should know that it nobody's fault - it's just the light.


This article is very good in explaining practically white / color balance and its perception by humans: http://www.ianplant.com/photo-tips-how-to-white-balance.htm
« Last Edit: November 06, 2012, 07:37:16 AM by NotABunny »

Zv

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Re: What is white balance and what's the correct way to use it?
« Reply #34 on: December 04, 2012, 09:32:41 AM »
See also my blog post on WB here -

http://zeebytes.blogspot.jp/2012/09/photography-101-white-balance.html?m=1


It also includes step by step info on setting a custom WB and simple explanations.
« Last Edit: December 04, 2012, 09:49:47 AM by Zv »
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Re: What is white balance and what's the correct way to use it?
« Reply #35 on: December 05, 2012, 01:21:19 AM »
There is something in this, that using serious tools you still achieve different results. One would expect, that serious tools should lead to objective, similar results.

This is a key point.  I agree that there is such a thing as 'correct' WB and color balance, but achieving it in practice is not simple.
WB is a completely subjective thing but generally, You want it accurate.

Different Light sources give out different shades of light, Tungsten is more orange, Florescent is greenish, daylight is bluer, Flash is always 5600K Etc.

The tint control allows you to tweak the Green-magenta to fine tune the color more.

You can Lie about the true colors on a scene with mixed lighting to impressive results.

Way back, I shot a bunch of pics in an old gym with lots of kids playing dodgeball.  The pictures looked terrible because of the light.  Super old mercury vapor lights.  Very weird color I couldn't totally fix in post.  So I looked into getting WB right in camera.  Fast forward to today... I usually just use the camera settings and tweak in Lightroom.  OTOH, when I shoot in that gym or I shoot an important event like a wedding, I use the WB tool.  Why not?  I've got it.  But most times, I don't even have it with me.

It sounds like you want a simple answer to a rather complex question.  The real question is what are your photography needs/goals for the images?  Go back and read the posts by neuro and RLPhoto.  That's real world common sense.  (The rest is solid and factual, very interesting but likely overkill for your needs.)  I think if you are like 90% of us and if you choose a WB tool, expodisc, WB LensCap, WhiBal, LastoLite, SpyderCube, Spirograph or Twister (with nice color dots), you'll be happy.  Get it as close as you can in camera, tweak it in Lightroom.  In most cases, simply keeping your camera set consistently (avoid AWB) will save time in post.  That's what I do.  Save the elegant WB calibration solutions like above for important but complicated mixed light scenarios and high expectations.  Don't overthink it unless you are shooting thousand dollar images in a studio for clients that are going to color match the images.  And if that's the case, you'll be learning how to use gels and filters, believe me!

RLPhoto has a point.  This is about achieving a certain result based in part on accuracy and in part on what YOU like.  I think we've ALL been obsessed with WB at one time or another and then eventually drift back to just using the camera settings most of the time.  Learn and know how to use custom WB on your camera and be good at it but don't miss shots or reduce the fun of it by obsessing too much with WB unless the needs/goals for the images dictate/demand the extra effort.
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Re: What is white balance and what's the correct way to use it?
« Reply #36 on: December 05, 2012, 03:12:33 AM »
I'm definitely in the "subjective" camp on how to approach white balance. But I don't argue with the kelvin scale or those who want an accurate/realistic white balance.

When I'm out shooting, the light temperature can be all over the place. And when I'm editing, I tend to think of the white balance sliders as creative tools, rather than "correction" tools. Sometimes, a life-like white balance works for me, but because I use split toning and HSL so much... the idea of being "realistic" gets tossed out the window.

Ultimately, I think the key is to have good monitor calibration, so regardless of your white balance preference, you know what your shots will look like when people see them. I regularly see color shifts and eye fatigue and editing room lighting can also throw off the end results. 

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Re: What is white balance and what's the correct way to use it?
« Reply #36 on: December 05, 2012, 03:12:33 AM »

AmbientLight

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Re: What is white balance and what's the correct way to use it?
« Reply #37 on: December 05, 2012, 04:22:44 AM »
My aim is always to reproduce colours looking as natural as possible. Therefore I fully agree with Mikael Risedal and Paul13Walnut5 to get it right in-camera. Using something like QPCard isn't taking up much time, so that is what I do. You can always tweak colours to your heart's content later on.

PeterJ

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Re: What is white balance and what's the correct way to use it?
« Reply #38 on: December 05, 2012, 06:42:12 AM »
B&W and be there :P

RustyTheGeek

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Re: What is white balance and what's the correct way to use it?
« Reply #39 on: December 05, 2012, 09:03:44 AM »
I'm definitely in the "subjective" camp on how to approach white balance. But I don't argue with the kelvin scale or those who want an accurate/realistic white balance.

When I'm out shooting, the light temperature can be all over the place. And when I'm editing, I tend to think of the white balance sliders as creative tools, rather than "correction" tools. Sometimes, a life-like white balance works for me, but because I use split toning and HSL so much... the idea of being "realistic" gets tossed out the window.

Ultimately, I think the key is to have good monitor calibration, so regardless of your white balance preference, you know what your shots will look like when people see them. I regularly see color shifts and eye fatigue and editing room lighting can also throw off the end results.

+1 & Ditto!
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neuroanatomist

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Re: What is white balance and what's the correct way to use it?
« Reply #40 on: December 05, 2012, 09:55:26 AM »
I tend to think of the white balance sliders as creative tools, rather than "correction" tools.

Agreed.  Plus...I'm lazy!  Why should I get up at 4am to catch that lovely pink sunrise lighting, when I can sleep in and just adjust temp and tint?!?   ::)
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Re: What is white balance and what's the correct way to use it?
« Reply #41 on: December 05, 2012, 10:57:30 AM »
There is also the almost separate discussion about art.  Let's face it, it's FUN to create amazing images using flash gels, various filters, etc.  And it's sometimes necessary to use those same tools to correct WB in tricky lighting situations.  Joe McNally refers to many times he has used filter/gel combos to correct for weird lighting at the shoot.  An example might be a magenta filter and green gel for mixed flourescent lighting with flash, etc.

The better photographer can determine what is impossible in post and what can be corrected with no worries.  Personally, most of the time when I'm on the go I concentrate on framing/composition, focus and things I can't fix in post.  I can usually deal with WB in post.  If I spend too much time worrying about WB, I will miss the shot being distracted changing settings, etc.  OTOH, if I am shooting portraits and spending 30 minutes on lighting anyway, I might as well spend another 30 seconds and get the WB right too.
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Re: What is white balance and what's the correct way to use it?
« Reply #42 on: December 06, 2012, 10:30:17 PM »
I tend to think of the white balance sliders as creative tools, rather than "correction" tools.

Agreed.  Plus...I'm lazy!  Why should I get up at 4am to catch that lovely pink sunrise lighting, when I can sleep in and just adjust temp and tint?!?   ::)

Well, to a point I suppose. If you have mixed lighting like this, correcting for the wrong WB can yield more pleasing results or a completely different shot.

IE: The "Correct" WB is the one on the Left.


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Re: What is white balance and what's the correct way to use it?
« Reply #42 on: December 06, 2012, 10:30:17 PM »

paul13walnut5

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Re: What is white balance and what's the correct way to use it?
« Reply #43 on: January 01, 2013, 10:23:30 PM »
And no, it is not subjective.  It is a science.  And it was a scientist from my home town that devised the Kelvin Scale.
Color science is pretty much meaningless without perception of color. Without perceptually derived sensitivity curves, how are we to determine what is "netural" or "flat"?

http://en.wikipedia.org/wiki/Color
"Color or colour (see spelling differences) is the visual perceptual property corresponding in humans to the categories called red, blue, yellow, green and others..."

-h

Hahaha!

What if the viewer is colour blind?

What if we are all slightly colour blind?

Did you not read the rest of my answer, or just choose to ignore the bits where I went onto say grade it etc in post?

White balance and colour temperature are technical concepts that exist and are provable and repeatable.

Subjective perception, not as much.

Happy new year, make it your resolution to get it right at the capture stage and play about with it later.  Much easier than deliberately getting it wrong in camera and trying to fix it later.

"Color science is pretty much meaningless...".   Good one, that!

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Re: What is white balance and what's the correct way to use it?
« Reply #44 on: January 02, 2013, 06:18:32 PM »
I carry around a Kodak color card I got way back in the film days..... top half neutral grey, bottom half color bars.

For things like sunlight or clouds I use the camera presets, they are usually close enough that an image can be easily adjusted to taste in lightroom. When I get confused with indoor lighting, I make a best guess at the settings, whip out the color card and take a shot of it, and then procede. When I get back I can use the color card shot to tell me what I need to adjust.

And shoot in raw.... you can change the color balance afterwards with raw files.... I have merrily snapped away dozens of photos before realizing that I had the balance set to tungsten BEFORE I moved outdoors and forgot to change it.... With RAW files you can correct that mistake.

Using the color card I was able to adjust white balance and hue until Fluffy turned white again....
« Last Edit: January 02, 2013, 08:50:05 PM by Don Haines »
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Re: What is white balance and what's the correct way to use it?
« Reply #44 on: January 02, 2013, 06:18:32 PM »