Setting White Balance

Camera: 50D

I have been using the Kelvin White Balance Setting more lately to control WB over a set of images, but have noticed that the setting I have it set to in camera, is not matching what shows up in ACR when I start to do my post work on my images.

Any reason for that, which one is more correct? TIA for any tips, pointers or help.

Adobe's Raw converters (ACR and Lightroom) use different multipliers than Canon's software.

Let me attempt to explain: When you import a Raw file into Adobe Camera Raw or Lightroom (or any other third-party raw converter), the program only utilizes four of the in-camera settings: ISO, aperture, shutter speed, and White Balance.

Of those four settings, ISO, aperture, and shutter speed are hardcoded into the EXIF metadata. Despite what we are led to believe, White Balance is simply a metadata tag that isn't hard-coded into the Raw file. This is what allows us to change the White Balance setting during post-production.

Unlike settings like aperture, shutter speed or ISO, Color temperature is not a tightly controlled parameter in digital imaging. The metadata tag simply describes how the colors should appear when converted to a rendered/rasterized/bi​tmapped file i.e. an RGB file.

Each Raw converter looks at the metadata tag and applies a multiplier (via color profiles) that translates the metadata tag into an actual color temperature number. Canon uses very different color profiles from Adobe so the multipliers are also different and the resulting temperature numbers produced are different.

Regardless of the variance between the Kelvin setting in the camera and how its interpreted in the Raw converter, white and neutral colors should still measure as white or neutral.

TRhoads wrote in post #12842396
Camera: 50D

I have been using the Kelvin White Balance Setting more lately to control WB over a set of images, but have noticed that the setting I have it set to in camera, is not matching what shows up in ACR when I start to do my post work on my images.

Any reason for that, which one is more correct? TIA for any tips, pointers or help.

ok, that makes sense, thanks for the great explanation. I won't wonder about it anymore. Thanks!

Keep track of something white in your image, or even place a white object there if possible..

During processing, use that known white object as your WB basis..

Ideally you want to include something spectrally neutral in your scene like a WhiBal card or an X-Rite ColorChecker Passport.

LarryD wrote in post #12842682
Keep track of something white in your image, or even place a white object there if possible..

During processing, use that known white object as your WB basis..

that has been my basic practice.

PixelMagic wrote in post #12842732
Ideally you want to include something spectrally neutral in your scene like a WhiBal card or an X-Rite ColorChecker Passport.

An Expodisc is in my future, just can't spare the $$ for one right now. I will have to look into the X-Rite thing, not heard of that one.

TRhoads wrote in post #12842737
An Expodisc is in my future, just can't spare the $$ for one right now. I will have to look into the X-Rite thing, not heard of that one.

In my opinion, the Expodisc and all of its clones are overly expensive and very inconvenient devices to use for white balance setup. Even though many folks use them incorrectly, the only correct way to use them is to aim the camera (with the Expodisc on the lens) AT THE LIGHT SOURCE.

The Expodisc is designed to screw into a lens like any ordinary filter. If you have multiple lenses with different filter thread sizes, you have two options. Buy an Expodisc for each filter size or buy one for the largest filter thread size you have. Used that way, though, the Expodisc is a pain in the you-know-where to use because you'll have to manually hold it in front of all your lenses except the ones with the correct thread size.

The Expodisc can ONLY be used to set up "custom white balance". There's no other possible way to use it for white balance compensation.

A neutral gray card, on the other hand, can be used to either set up a Custom White Balance or it can be used by merely placing the card in the scene for a single test shot. For the second method, it's best to shoot in RAW mode. Then, during RAW conversion, you can use an "eyedropper" tool in the software to sample the gray card and you have the proper white balance. Then, you can use the numbers that appear as a result for a batch conversion of the rest of the shots done in the same light.

You can buy a truly neutral gray card for as little as about $20 these days, and it is far more versatile than the Expodisc and its clones.

SkipD wrote in post #12843301
You can buy a truly neutral gray card for as little as about $20 these days, and it is far more versatile than the Expodisc and its clones.

I picked up the PhotoVision pop-up pocket calibration target. It's divided into three sections on the front - black, 18%, white - and on the back it's a silver reflector. It folds down into a 6" disc to fit easily in a bag. Pretty handy! Works nicely for white balance as well as exposure, and having an extra reflector on hand is never a bad idea.

http://www.amazon.com …/B000E44QNE/ref​=pd_cp_p_4

While I agree with almost everything you said, the comment that "The Expodisc can ONLY be used to set up "custom white balance". There's no other possible way to use it for white balance compensation." isn't entirely accurate.

Although it isn't the way an Expodisc is commonly used, you can aim it at the light source and take a WB reference shot; then complete your shoot using Auto WB or any other WB setting.

Later in your Raw converter you click the WB Tool on the Expodisc Reference shot to produce the corrected WB. Then you simply transfer that WB setting to the other photos in the shoot. In applications like Adobe Camera Raw and Lightroom its a simple matter of just "syncing" the WB from the corrected reference photo to the others.

SkipD wrote in post #12843301
In my opinion, the Expodisc and all of its clones are overly expensive and very inconvenient devices to use for white balance setup. Even though many folks use them incorrectly, the only correct way to use them is to aim the camera (with the Expodisc on the lens) AT THE LIGHT SOURCE.

The Expodisc is designed to screw into a lens like any ordinary filter. If you have multiple lenses with different filter thread sizes, you have two options. Buy an Expodisc for each filter size or buy one for the largest filter thread size you have. Used that way, though, the Expodisc is a pain in the you-know-where to use because you'll have to manually hold it in front of all your lenses except the ones with the correct thread size.

The Expodisc can ONLY be used to set up "custom white balance". There's no other possible way to use it for white balance compensation.

A neutral gray card, on the other hand, can be used to either set up a Custom White Balance or it can be used by merely placing the card in the scene for a single test shot. For the second method, it's best to shoot in RAW mode. Then, during RAW conversion, you can use an "eyedropper" tool in the software to sample the gray card and you have the proper white balance. Then, you can use the numbers that appear as a result for a batch conversion of the rest of the shots done in the same light.

You can buy a truly neutral gray card for as little as about $20 these days, and it is far more versatile than the Expodisc and its clones.

PixelMagic wrote in post #12843453
While I agree with almost everything you said, the comment that "The Expodisc can ONLY be used to set up "custom white balance". There's no other possible way to use it for white balance compensation." isn't entirely accurate.

Although it isn't the way an Expodisc is commonly used, you can aim it at the light source and take a WB reference shot; then complete your shoot using Auto WB or any other WB setting.

Later in your Raw converter you click the WB Tool on the Expodisc Reference shot to produce the corrected WB. Then you simply transfer that WB setting to the other photos in the shoot. In applications like Adobe Camera Raw and Lightroom its a simple matter of just "syncing" the WB from the corrected reference photo to the others.

Thanks for that information.

SkipD wrote in post #12843301
In my opinion, the Expodisc and all of its clones are overly expensive and very inconvenient devices to use for white balance setup. Even though many folks use them incorrectly, the only correct way to use them is to aim the camera (with the Expodisc on the lens) AT THE LIGHT SOURCE.

The Expodisc is designed to screw into a lens like any ordinary filter. If you have multiple lenses with different filter thread sizes, you have two options. Buy an Expodisc for each filter size or buy one for the largest filter thread size you have. Used that way, though, the Expodisc is a pain in the you-know-where to use because you'll have to manually hold it in front of all your lenses except the ones with the correct thread size.

The Expodisc can ONLY be used to set up "custom white balance". There's no other possible way to use it for white balance compensation.

A neutral gray card, on the other hand, can be used to either set up a Custom White Balance or it can be used by merely placing the card in the scene for a single test shot. For the second method, it's best to shoot in RAW mode. Then, during RAW conversion, you can use an "eyedropper" tool in the software to sample the gray card and you have the proper white balance. Then, you can use the numbers that appear as a result for a batch conversion of the rest of the shots done in the same light.

You can buy a truly neutral gray card for as little as about $20 these days, and it is far more versatile than the Expodisc and its clones.

Had I decided to spend the $$ on one, I was going to get the 82mm one and handhold when I needed it...since reading some of the other tips in this thread, I have ordered the X-Rite white balance card, it does what I want, lets me set WB for the scene I am in, mainly outdoors, and then I don't have to worry about variation in my images, and it is less $$, so I can buy other gadgets. And I only shoot in RAW. For the reasons you mentioned.

Expo Disc is awesome. I usually just take a picture from my subject's perspective if possible (so facing my eventual camera position). Having only recently picked up the 77mm size off of CL for what I thought was a good deal, I sometimes forget to use it but usually remember before I move on and take a reference picture for later use in post processing. I also don't have any 82mm filter size lenses, but do have 72mm (135L) and 58mm (50/1.4), but dont find it a bother to use with them by just holding it in front of the lens.

thanks for the information about the kelvin setting being different, makes sense!

I don't have any lens that is 82mm either...yet. But I thought I would just buy it bigger than my current largest lens size of 77. I know the Expodisc has to be pointed at the light source, which is what I want it mainly for, when working with my new studio lights that I am slowly acquiring, outdoors I don't know if it would work as well, which is why I am getting the white balance card... rambling now.

You're welcome.

What you described is applicable to JPEG where it becomes critical to get the WB set in-camera. Of course JPEGs can also be modified in a raw converter but its much harder to do.

SkipD wrote in post #12843563
Thanks for that information.

Did you get the X-Rite white balance card or the ColorChecker Passport? The CCP is expensive (approx $100) but its very versatile and can be used to calibrate you camera's sensor output to a known color standard. by creating custom profiles.

TRhoads wrote in post #12843564
Had I decided to spend the $$ on one, I was going to get the 82mm one and handhold when I needed it...since reading some of the other tips in this thread, I have ordered the X-Rite white balance card, it does what I want, lets me set WB for the scene I am in, mainly outdoors, and then I don't have to worry about variation in my images, and it is less $$, so I can buy other gadgets. And I only shoot in RAW. For the reasons you mentioned.