Another thread about White balance and RAW

[MrGibbage]

One thing's certain--there's a lot of information here about white balance and shooting RAW. I have been shooting for a few years (a lot of off-camera flash shots on manual, plus a wide variety of on-camera flash and natural light shots), and exclusively in RAW. However, I have always left my camera in AWB. One thing that has bugged me is the inconsistent appearance of the shots on the back of my camera and on initial import into Lightroom/Camera Raw. It never bugged me too much because I always knew I could fix it in post processing. But lately I've been wondering if my pictures weren't suffering, if even a little, because I didn't get it right in camera. So I came here looking for answers. A lot of people recommend setting the camera to one of the other settings (cloudy, tungsten, whatever), but take it off AWB. OK, this makes sense. I should want to take as much control over the photo as possible. But then I got to thinking about it. Doesn't choosing one of those settings just tell the camera what target to aim for when displaying the image? In other words, the camera is still doing calculations. It's not at all like a manual setting for shutter speed and aperture. So, since the camera still has to do calculations, won't there still be variability between images?

This might be a good place to ask, what is the target for AWB? It's easy to explain the target for the program modes for exposure, and correct me if I am wrong, but doesn't AWB just try and "line up the humps" in the histogram so there isn't a color cast? Is that the target? And then, what happens in camera when you choose "shade"? Does it leave in a small amount of blue cast to make it look shady? Or does it take away more blue to remove the effects of shooting in the shade? Or something else altogether? Or maybe we really don't know because Canon won't tell us.

Thanks in advance.

Skip

[Shooting]

I tried raw and hate it..I shoot exclusively jpeg and CS3 lets you work with jpegs in the raw editor..but to answer your question, I have heard photographers say that even though it can be fixed in post, set your white balance according to the light you are using or in.

[welkcar]

i always shoot in RAW and that's not going to change. regarding the whitebalance setting, i generally try to set it to the conditions i'm exposed to. since i sometimes am showing the images to my customer before i have the chance to set the WB in PP. (i show some wedding photos at wedding receptions) if i get lazy, AWB is it, but sometimes it is not reliable.

[René Damkot]

IMO WB doesn't make a lick of difference if you shoot Raw, unless you use the histogram to judge exposure.

Link (http://www.ppmag.com/web-exclusives/2007/11/white-balance-the-secret-)

[Dan-o]

Do a test. Shoot indoors with AWB and with a grey card custom WB and check for yourself.

[feilb]

Shooting in raw, it makes no difference what you select in terms of WB.

No matter what you set your camera to (AWB, Cloudy, etc) the sensor always recieves the same temperature of light (WB Temperature wise). WB settings are a processing step that happens after the image has been collected as it is being processed into JPG. Because RAW files are just that- raw, unprocessed sensor information - you are not getting any benefit by getting the "right" WB in camera* because your settings are applied to nothing other than the thumbnail image (jpg) which is embedded within the raw file for on camera image preview.

Many raw processors, however, will take the camera's suggested setting and roll it into the default image you see in photoshop or the like (As Shot). This does not mean that all of the information that your camera uses to process raw data into JPG files isnt still there, though.

* Some camera's have the ability to view RGB histograms. Some people use these to judge whether or not a channel is clipping. WB settings may change the shape of this histogram graph (though clipping will not be affected) but once again will not affect the amount of information the camera captures from the sensor.

As for what AWB is striving for, it basically searches the image for what it approximates to be a near neutral color (grays/near whites) and tries to make the color truly neutral (ie R,G, and B values are all equal) by applying color correction to the image as a whole.

Some settings and what they assume:

Cloudy: light will have slight bluish cast (higher color temperature, yet ironically called cooler) so adjust and make the image warmer (lower color temperature, yet ironically called warmer)

Shade: stronger bluish cast due to ambient light from the blue sky in the shade, warm the image up more (see above)

Sunny: light pretty much neutral, process as such

Tungsten (incandescent): light will be very warm (low color temperature) so cool it off (raise color temperature, or make it more bluish i guess you would say)

Florescent: light will be cool (bluish, high CT) with a slight greenish cast, warm up slightly and adjust image to have more magenta. (sometimes flourescent will have a couple different versions playing with the green/magenta ratio)

Ultimately the goal of white balance is to make whites and grays as neutral as possible, thereby giving correct impressions of color.

[PhotosGuy]

As for what AWB is striving for, it basically searches the image for what it approximates to be a near neutral color (grays/near whites) and tries to make the color truly neutral (ie R,G, and B values are all equal) by applying color correction to the image as a whole. I agree. Some people say that it's pretty close in daylight. I still shoot RAW 99% & use Custom or a pre-set there so I start out close to correct.

One thing to always keep in mind is that the "correct" WB may not be the "right" WB for a shot? Don't we like warm sunsets?

As for indoors, AWB isn't very good there. Notice that the very last exposure in the 2nd group of tests was of a gray card, & it's way off.
http://photography-on-the.net/forum/showthread.php?t=54281

Waiting to adjust WB after shooting RAW may be a mistake. Curtis N found that a blown red channel is a problem & there's been a lot of discussion on that:
How NOT to expose to the right (http://photography-on-the.net/forum/showthread.php?t=93712)

How to fix it:
Restore Those Clipped Channels (http://www.luminous-landscape.com/tutorials/restore-clipped.shtml)

[tzalman]

* Some camera's have the ability to view RGB histograms. Some people use these to judge whether or not a channel is clipping. WB settings may change the shape of this histogram graph (though clipping will not be affected) but once again will not affect the amount of information the camera captures from the sensor.

This is not true. Clipping can definitely be affected and, in fact, can often be caused by the white balance. WB is done by pushing up the blue and the red channels relative the the green. For instance, the multipliers for sunlight are in the area of Bx1.4 and Rx2.0. The sensor array is most sensitive to green, which is why it is held constant while the other two are strengthened. Let's suppose you have a properly exposed grey card that has RAW values of 60/120/86. Click on it with the grey probe to make it 120/120/120. In the same photo there is a bright red flower, which the sensor read as 150/216/140. When WB is applied that becomes a theoretical 300/216/196 or a real 255/216/196. The red channel which was not blown in the RAW is now fried.

In an attempt to prevent this happening in the jpg thumbnail, some people use a custom WB called the UniWB:
http://photography-on-the.net/forum/showthread.php?t=442096&highlight=uniwb
http://photography-on-the.net/forum/showthread.php?t=485349&highlight=uniwb

[qtaran111]

Thanks for that tzalman. I assume this is the reason why sometimes when converting the RAW if you change the white balance you will see some of the highlights clip? Sometimes even small changes of white balance in contrasty images (i.e. going from daylight to cloudy) will show blown highlights. I guess this is because as the image is warmed the red channel is increased (and vice versa cooled -- blue).

I also agree with Frank that a lot of the time WB is subjective, depending on the mood you are trying to achieve.

[tzalman]

The great thing about RAW is that if you know the blown channel is unblown on the RAW you can simply reduce Exposure (in my example above reducing Exposure by 1.33 stops would make the flower 248/164/88) and then use curves or Fill Light or some other method that doesn't touch the highlights to adjust the shadows and midtone.

[MrGibbage]

If I am understanding this all correctly, changing the WB setting does not directly affect what is recorded by the sensor. It does, however, affect how the image is displayed on the camera and how the histogram is displayed. Because it affects the histogram, it can cause you to blow out highlights, for example, when exposing to the right.

Did I get it right?

Skip

[spcalan]

I think the only reason I shoot RAW is because DPP allows me to fix the white balance.
Since that is all I do in DPP.

[PhotosGuy]

Because it affects the histogram, it can cause you to blow out highlights, for example, when exposing to the right.
Did I get it right? That works for me. There's a lot of latitude for post corrections in RAW, & remember that all the highlights might not be worth saving in the first place. Since that is all I do in DPP. You should try to make all the changes you need before conversion since those changes will effectively be made in the 12-bit environment.

[spcalan]

What is your workflow in DPP?
I find DPP stubborn, except for WB and exposure.

[Shooting]

I know a photographer sets his WB on auto and shoots all day at a wedding..I was a 2nd. shooter to him once and he said just shoot, he could care less about WB because no matter what you set your camera on RAW doesn't read it and he fixes it all in Bridge.

[JohnJ80]

I tried raw and hate it.

Why?

J.

[René Damkot]

What is your workflow in DPP?
I find DPP stubborn, except for WB and exposure.
Why?
Have a look at these tutorials. (http://www.usa.canon.com/content/dpp2/index.html)

[feilb]

This is not true. Clipping can definitely be affected

I guess that is true for processed images. I was more or less thinking of situations where there is so much signal to one channel that it will clip regardless of your WB setting.

If I am understanding this all correctly, changing the WB setting does not directly affect what is recorded by the sensor.

Correct

It does, however, affect how the image is displayed on the camera and how the histogram is displayed. Because it affects the histogram, it can cause you to blow out highlights, for example, when exposing to the right.

Again, i don't know 100% whether the histogram of a raw image is based on the processed and embedded JPG, but if it is, then this is true. If it is an objective representation of the captured data, then it will make no difference. I don't have a camera near me right now to test.

[tzalman]

Again, i don't know 100% whether the histogram of a raw image is based on the processed and embedded JPG, but if it is, then this is true. If it is an objective representation of the captured data, then it will make no difference. I don't have a camera near me right now to test.
Unfortunately, the camera's histogram(s) is taken from the jpg. It would be nice to have a capture histogram, but not only do I know off no camera that provides one, I also know of only one converter that does so (UFRaw)

[Shooting]

Why?

J.

Since NONE of your menu settings are processed and are totally bypassed, you have to adjust every little thing yourself that the camera software does anyway. You have to do sharpening, saturation, etc..all that can be done in camera automatically. I shot raw for 2 years and got fed up with it all. I set my camera to do what I want and I'm satisfied with the results. Plus jpeg is universal..raw is too manufacturer proprietary and there is no set standard...Plus in a few years the early raw files like from this year won't even be read..Nikon users faced that a few years ago..

[JohnJ80]

Since NONE of your menu settings are processed and are totally bypassed, you have to adjust every little thing yourself that the camera software does anyway. You have to do sharpening, saturation, etc..all that can be done in camera automatically. I shot raw for 2 years and got fed up with it all. I set my camera to do what I want and I'm satisfied with the results. Plus jpeg is universal..raw is too manufacturer proprietary and there is no set standard...Plus in a few years the early raw files like from this year won't even be read..Nikon users faced that a few years ago..

I guess I have another set of defaults in LR that it automatically applies whenever I import images. It also takes some of the data from the camera and uses that (like white balance).

Is that not the same as what you describe?

There certainly is no need to "adjust every little thing" in my workflow as a result.

I agree with you about the RAW files' proprietary format problem. I convert them to DNG upon import which solves that problem.

J.

[Shooting]

Yes..white balance, color, sharpness, saturation, etc..the items on the menu in your camera you can set are all bypassed....so anything bypassed means you have to do it yourself...I prefer having my camera do exactly what I want and it can do it much faster than I can and more consistently.

[JohnJ80]

Right. And you can set these all as presets in LR. When you import they are automatically done just as if they were in your camera - unless I'm misunderstanding you. There is no additional time or settings required by the user to get the presets applied to the image.

j.

[cdifoto]

Yes..white balance, color, sharpness, saturation, etc..the items on the menu in your camera you can set are all bypassed....so anything bypassed means you have to do it yourself...I prefer having my camera do exactly what I want and it can do it much faster than I can and more consistently.
In-camera settings are not bypassed. They're used as a starting point. In DPP they're pretty much spot on since Canon knows Canon and in other softwares they're a best guess (and usually pretty close in the better ones).

As for white balance, for the first time at a wedding I set mine to 5500K and had consistency across the board and as a result much better image quality than ever before. 5500K is open daylight so it was spot on there, and it's only about 1000K off of shade so a single adjustment with a sync in Lightroom for all the images shot in the shade corrected that. No more eyedropper BS due to AWB variance and no need to change a vast majority of the images (even those indoors with flash).