Auto White Balance is an Abomination!

11/19/2007 04:06:58 PM · #76

Originally posted by GeneralE:

Here's an example to pick at -- I'm color-blind, so I often miss subtle color casts/shifts, so feel free to point out any oddities. In this more-or-less candid portrait, Isaac was backlit with an overcast sky, wearing a green jacket and orange shirt ... what could/should I do differently?

AWB did very well here. It's a little on the warm side, but that works for portraits IMO. Here's a slightly neutralized version: see photographer's comments for procedure. You can see where AWB was slightly fooled by the predominately quite neutral subject and the intense blue/green of the bg to try to warm things up a tad, when you compare the two.

R.

Message edited by author 2007-11-19 16:08:50.

Canon EF 24-70mm f/2.8L USM

11/19/2007 04:13:24 PM · #77

Originally posted by dwterry:

Great info Bear! Now, wouldn't it be nice if we could just "compress" this thread down to the important and pertinent info so that others could use it as a resource?

Done:

How AWB Works

R.

dwterry

Canon EOS-1D Mark III

11/19/2007 05:06:43 PM · #78

Originally posted by GeneralE:

This is pretty good. Now, if you back up to get more of the orange shirt into the image, you'll see a different cast to the boy's face (the more orange you include in the image, the bluer his face will go).

Apple iPhone 5

Nikon AF-S DX Zoom-Nikkor 18-55mm f/3.5-5.6 ED

11/19/2007 05:31:45 PM · #79

There are two scenarios I can think of which will change how someone achieves a WB they're happy with;

1) They want white to be pure white (as in the example of the wedding dress, or stock photography) - In this case neither AWB or any of the presets will get it *exactly* right. So either CWB during shooting or using a WhiBal card and setting the white point in post-processing.

2) The photographer wants to warm up the image. e.g. landscape shots. As mentioned in this thread, the 'cloudy' pre-set works well. Or just shoot using any of the WB pre-sets and then bump up the WB slider in post-processing.

As travis pointed out, since you'll have to do work on the RAW image anyway, does it really matter how far off the WB setting is when you start editing? In fact, CWB is the only mode where you are guaranteed to get the white balance exactly right and theoretically need no pp adjustments.

Gordon

RIM BlackBerry Curve

Canon EF 85mm f/1.8 USM

11/19/2007 05:38:28 PM · #80

Originally posted by jhonan:

As travis pointed out, since you'll have to do work on the RAW image anyway, does it really matter how far off the WB setting is when you start editing?

It depends. Do you ever look at the preview on the back of your camera ? If not, then no - it probably doesn't matter. Otherwise, I find I can be quite influenced in my composition and approach by the colour and quality of the light - blue for moodier shots, etc. Picking approximately the right white balance influences a lot of how I approach and work a scene.

Probably also depends how focused on colour you are in your compositions.

MikeJ

Canon EOS-1D Mark II

Canon EF 24-70mm f/2.8L USM

11/19/2007 06:53:50 PM · #81

Originally posted by dwterry:

Originally posted by MikeJ:
I'm glad to see the thread finally come to it's senses and swing back the other way. No one needs to fear using AWB.

Wait... I musta missed that part of the thread (other than if you're shooting raw, I mean). I would still contend that AWB should only rarely be used, and then, only under specific circumstances where it makes sense or as a last resort when you don't really have a choice. Otherwise, you just can't predict what you're going to get out of your camera.

It's there, you just have to squint a tiny bit and tilt your head to the right.

Originally posted by dwterry:

Originally posted by MikeJ:

Now what is bad is those that don't use their histogram. For shame.

Sounds like another good thread. You wanna start this one? :-)

(we gotta do something to keep people from spending ALL of their time arguing about climate change)

LOL! You think I'm nuts? Actually, I think I have posted on the use of histograms and improving your exposure and even how to use it in a pinch when you don't have a flash meter. But it might have been in the "who invented the internet" thread. But it would be a good thread for those that never use it or don't know what it's good for.

Mike

Message edited by author 2007-11-19 18:57:19.

Olympus 14-54mm f/2.8-3.5 Zuiko Digital Zoom

11/19/2007 08:08:00 PM · #82

[thumb]614923[/thumb]

Sorry about the horrid lighting, but wanted to show what AWB can do under bad lighting conditions.

This series was shot consecutively under a compact florescent bulb. To make things worse, the walls of the room are blue and a computer monitor is in the background. The room has a brown tile floor too.

The first shot is the camera's chosen WB. Not too good.

The second is using a WhiBal card and most resembles my flesh tone.

The third, while close, does exhibit a bit of a cast.

I was going to do a forth using a preset in ACR, but couldn't find a preset that looked anywhere near correct.

Message edited by author 2007-11-19 22:08:35.

MQuinn

Olympus OM-D E-M1

11/19/2007 08:21:19 PM · #83

This is one thing that I really miss about my E500 one touch WB, put a white peice of paper in front of the camera hit the button its adjusted for the lighting, man that was slick.

Apple iPhone 5

Nikon AF-S DX Zoom-Nikkor 18-55mm f/3.5-5.6 ED

11/19/2007 09:47:16 PM · #84

Originally posted by fotomann_forever:

I was going to do a forth using a preset in ACR, but couldn't find a preset that looked anywhere near correct.

What does your camera's 'fluorescent' WB preset look like?

Nikon AF-S DX Zoom-Nikkor 18-55mm f/3.5-5.6 ED

11/19/2007 09:55:42 PM · #85

Originally posted by jhonan:

Originally posted by fotomann_forever:
I was going to do a forth using a preset in ACR, but couldn't find a preset that looked anywhere near correct.

What does your camera's 'fluorescent' WB preset look like?

Looked like I had liver failure.
[thumb]614943[/thumb]

Apple iPhone 5

11/19/2007 09:56:32 PM · #86

Originally posted by fotomann_forever:

Looked like I had liver failure.

Lol! - Indeed! That's a terrible colour cast on that example.

edit: I am now even more convinced that the most accurate WB is achieved using a whibal card and then setting grey point from this in RAW post processing.

Message edited by author 2007-11-19 22:02:46.

Canon EF 24-70mm f/2.8L USM

11/20/2007 12:31:26 AM · #87

Originally posted by msieglerfr:

Maybe it a point of view of a Canon user, but I personally feel comfortable to use the AWB.

I agree. I'm comfortable using AWB most of the time. Not to start a brand debate, but all those who've complained about AWB being inaccurate seem to use Canons. My D200 works fine on AWB, with perhaps a few minor tweaks here and there to get things where I want them to be. If I'm shooting multiple shots under similar lighting, I use a WhiBal anyway, so there's no need to waste time setting WB to the particular setting when it's a 3-click process in LR.

Are the Canons THAT bad at white balance?

Message edited by author 2007-11-20 00:32:02.

dwterry

Canon EOS-1D Mark III

11/20/2007 12:34:38 AM · #88

You guys are being silly. AWB is *not* a brand thing.

I've suggested a very easy experiment for you to try. If you need me to give instructions again, I'll be happy to walk you through it. You can prove it to yourself with YOUR camera - regardless of brand.

AWB gives YOUR camera permission to change the color temperature of the captured scene based on WHATEVER IS IN the scene. That's how it figures it out. It looks at what is in the scene and tries to neutralize the color.

TRY IT. Stop trying to convince yourself that AWB is "okay" and go try the experiment.

11/20/2007 12:39:23 AM · #89

Originally posted by dwterry:

TRY IT. Stop trying to convince yourself that AWB is "okay" and go try the experiment.

Yeah, let's see some more mug shots :-D

11/20/2007 01:16:36 AM · #90

Originally posted by dwterry:

Instead, stop trying to convince ME and calling me silly. I don't really care if two shots under the same lighting are off by 5 degrees K, because I've already said that I calibrate them later with a WhiBal so that the colour temperature is identical (and bang-on, as opposed to just being approximate had I used a camera preset).

I have other things to think of while I'm photographing, and WB doesn't consume my time. I'm glad it doesn't, since my camera gets the AWB as close as I need it to be--every time.

11/20/2007 01:38:07 AM · #91

Originally posted by dwterry:

TRY IT. Stop trying to convince yourself that AWB is "okay" and go try the experiment.

Here:

[thumb]615001[/thumb]
[thumb]615002[/thumb]
[thumb]615003[/thumb]

Different angles and focal lengths. Different amounts of green and blue in each photo. And yet, all three came out with white balance of 3050 and -3. Before even trying to guess which custom WB setting to use, I was done.

11/20/2007 01:44:33 AM · #92

Originally posted by geoffb:

Originally posted by dwterry:
TRY IT. Stop trying to convince yourself that AWB is "okay" and go try the experiment.

Here:

[thumb]615001[/thumb]
[thumb]615002[/thumb]
[thumb]615003[/thumb]

Different angles and focal lengths. Different amounts of green and blue in each photo. And yet, all three came out with white balance of 3050 and -3. Before even trying to guess which custom WB setting to use, I was done.

To appease you, I then went back and took another picture on each WB preset, and then another picture with the WhiBal. None of the preset WB settings looked close to the "proper" white balance, which I was easily able to set all the images to by syncing the WB of all the shots to that of the corrected image.

11/20/2007 01:55:11 AM · #93

GeoffB, you're kind of missing the point. The idea is to shoot a scene at different zoom lengths where the dominant color in the image changes radically depending on how much you zoom. AWB will always do a pretty decent job on a predominately neutral scene; that is what it's designed for, and it works very well.

Look, get yourself a large piece of something blue, or pink, or whatever, a strong color, and pin it to the wall. Illuminate it with tungsten light. Frame the shot so it is pretty much filled witht he color field, just a little white wall at the edges. Shoot once at tungsten WB and once at auto WB, and compare the difference, OK?

You'll see what we are talking about.

R.

Message edited by author 2007-11-20 01:55:40.

11/20/2007 02:08:25 AM · #94

Originally posted by Bear_Music:

GeoffB, you're kind of missing the point.

I get your point. I'm just saying, in agreement with

Mr_Pants, that I may as well leave the camera on AWB and do any adjustments quickly and easily as a batch process later.

Originally posted by Bear_Music:

Look, get yourself a large piece of something blue, or pink, or whatever, a strong color, and pin it to the wall. Illuminate it with tungsten light. Frame the shot so it is pretty much filled witht he color field, just a little white wall at the edges. Shoot once at tungsten WB and once at auto WB, and compare the difference, OK?

You'll see what we are talking about.

R.

I used my Christmas tree in 3/4 of the frame, with the white wall behind it in the other 1/4. One shot on AWB and the other on tungsten. Both came out to identical WB settings.

11/20/2007 02:51:15 AM · #95

Originally posted by geoffb:

I used my Christmas tree in 3/4 of the frame, with the white wall behind it in the other 1/4. One shot on AWB and the other on tungsten. Both came out to identical WB settings.

From a WB perspective, green is a pretty neutral color. AWB usually performs well with greens. Seriously, try this with some sort of dramatic red or blue card on a white wall to illustrate the point.

But in the end you are correct in this; if you shoot RAW, it doesn't much matter except in workflow streamlining, if even there. These WB issues are more directed at JPG shooters, where understanding of how AWB works and when it is best not to use it are pretty critical.

R.

11/20/2007 02:57:12 AM · #96

Originally posted by Bear_Music:

But in the end ... if you shoot RAW, it doesn't much matter except in workflow streamlining, if even there. These WB issues are more directed at JPG shooters, where understanding of how AWB works and when it is best not to use it are pretty critical.

R.

I totally agree with you here. WB is absolutely crucial for someone shooting in JPEG, and I would then wholeheartedly support what you and

DWTerry (among a few others) are saying.

Interesting to know about green's relative neutrality when it comes to white balance, though.

11/20/2007 03:14:25 AM · #97

Originally posted by geoffb:

Interesting to know about green's relative neutrality when it comes to white balance, though.

It's no surprise; when dealing with natural light and tungsten light, the WB comes down to "how warm is the light?" (which is a blue/yellow issue). It's only when we get into strongly artificial light sources (flouresecents, metal halides, and such) that we start to get the green/magenta component into the equation.

Since green is a mix of blue and yellow, it tends to be WB-neutral if it is a relatively neutral green to begin with, which Christmas trees are.

R.

11/20/2007 03:23:34 AM · #98

<===== Just learned something he did not know.

11/20/2007 03:32:30 AM · #99

Originally posted by fotomann_forever:

<===== Just learned something he did not know.

And what's that, Leroy?

R.