RAW white balance - Canon 5D

[DrJeans]

Hi, I have a Canon 5D. When the shoot in RAW manual white balance, you get different files RAW. It depends on the color temperature. Now the question: All changes are recorded in RAW at the moment when the data is read from the matrix or a correction only metadata for RAW? RAW files do have a difference in the change of color temperature or every RAW is a replica of the matrix does not depend.

Thanks for any information and links to documentation.

[rogerb]

Hi DrJeans:

If I understand your question correctly, the answer is that the image part of the raw files doesn't change when you change the white balance in your camera. However there is a separate part of the file that contains other information, like your "shooting style", and "white balance", etc.

This part tells your raw converter software how to apply white balance to the raw file during conversion. This is why, when I shoot raw, I just leave white balance on AUTO and then tweak it during raw conversion. In fact, you can even set your camera to "Monochrome" and you can tell the raw converter to change it back to color by restoring saturation. That's the beauty of raw files. You can do so much with them.

I hope this helps.
Roger

[arith]

This is very helpful to me; I do not understand why I should go to the trouble to set white balance at all, just leave it on 5600 kelvin.

Then I can choose balance later.

[rogerb]

This is very helpful to me; I do not understand why I should go to the trouble to set white balance at all, just leave it on 5600 kelvin.

Then I can choose balance later.

Yes, you can do that but you'll probably have to adjust it on a large percentage of your photos since lighting can vary quite a bit. If you set it to AUTO then you only have to adjust if you feel the camera has not chosen the right white balance setting.

Also remember that the image shown on the camera's lcd is affected by the white balance setting of the camera which could be misleading during review if the lighting is quite different from your manual 5200K setting.

[DrJeans]

Hi rogerb! Thanks for your reply.

Assume that everything that happens so, but RAW files are different in all editors: DPP, ACDSee, PS. I can not agree, but Canon describes:

Also included on the camera is ultra-precise white balance with nine types of white balance settings, white balance bracketing (blue-amber and magenta-green, even on RAW and RAW+JPEG shots) and white balance correction.

I want to understand the technical process. Here the author writes that the wrong white balance leads to the color noise. If RAW - cast matrix, how WB affect noise?

In fact, you can even set your camera to "Monochrome" and you can tell the raw converter to change it back to color by restoring saturation. That's the beauty of raw files. You can do so much with them.

I totally agree, it is stated in the instructions manual Canon EOS 5D, p.54

RAW images captured with the [Monochrome] setting can be converted into color images with the bundled software

[rogerb]

Hi rogerb! Thanks for your reply.

Assume that everything that happens so, but RAW files are different in all editors: DPP, ACDSee, PS. I can not agree, but Canon describes:

Perhaps there is a Canon guru in the group who can provide more insight but my interpretation of the above is that the bracketing of white balance is carried over in metadata of the raw files to allow DPP to display the images appropriately. Bracketing of white balance in the camera would provide a definite benefit when shooting jpeg or raw + jpeg but I don't see a real advantage when shooting raw only.

[DrJeans]

Bracketing of white balance in the camera would provide a definite benefit when shooting jpeg or raw + jpeg but I don't see a real advantage when shooting raw only.

rogerb, always shooting mode RAW + JPG?

[rogerb]

rogerb, always shooting mode RAW + JPG?

I personally shoot raw only but if you are shooting raw + jpeg, you can benefit from white balance bracketing in camera because you can choose later which jpeg file looks best. It is very difficult if not impossible to effect a white balance adjustment on a jpeg file in post-processing and the result is a degraded image quality so bracketing in camera is the preferred way to go if you want to use jpeg.

Please bear in mind that I am not an expert in this field. Perhaps someone in the group can provide more detailed information on this subject.

Roger

[DrJeans]

rogerb, I shoot raw only. My interest was in doubt. Until then assumed that the AWB for raw only enough now not so sure. So I was searching for a new place to communicate with photographers.

[rogerb]

Sergey:

Here is a quote from the Canon Learning Center:

"If you shoot RAW images, you can change your White Balance while editing, regardless of your camera settings at the time of shooting."

( http://www.usa.canon.com/dlc/control...articleID=2666 }

Different camera manufacturers handle raw formats in various ways. My understanding is that Canon treats the raw file as containing raw data and appends shooting information to it, rather than modifying it.

[Colin Southern]

I personally shoot raw only but if you are shooting raw + jpeg, you can benefit from white balance bracketing in camera because you can choose later which jpeg file looks best. It is very difficult if not impossible to effect a white balance adjustment on a jpeg file in post-processing and the result is a degraded image quality so bracketing in camera is the preferred way to go if you want to use jpeg.

Please bear in mind that I am not an expert in this field. Perhaps someone in the group can provide more detailed information on this subject.

Roger

Hi Roger,

With RAW, all manufacturers simply pass a white balance tag back to the post-processing software as a metadata tag (along with a lot of other metadata). The software can do whatever it likes with this metadata; in the case of ACR (Adobe Camera RAW) it pretty much ignores everything except white balance, but the white balance it does use is only the "as shot" starting point.

White balance adjustment is essentially lossless on a RAW file - it's not often we get a "free lunch" in photography, but this is about as close as we get. Later versions of ACR (as shipped with CS3 and CS4) CAN however process JPEG files - however - it's really only a "simulation" as a JPEG just doesn't have the same physical properties as a RAW capture.

The bottom line is that ANY processing on a JPEG file results in image degradation - but that's not necessarily a "show stopper"; the final result might be perfectly acceptable - it all comes down to how much info was contained in the file to start with, and how big the shifts were. In practice, small white balance shifts to JPEGs are pretty harmless - what really clobbers a JPEG is trying to raise shadow detail large amounts.

Hope this helps someone!

[Colin Southern]

Hi, I have a Canon 5D. When the shoot in RAW manual white balance, you get different files RAW. It depends on the color temperature. Now the question: All changes are recorded in RAW at the moment when the data is read from the matrix or a correction only metadata for RAW? RAW files do have a difference in the change of color temperature or every RAW is a replica of the matrix does not depend.

Thanks for any information and links to documentation.

Hi Sergey,

In terms of white balance, what's contained in a RAW file is pretty much just a dump of the sensor + associated metadata.

I can't speak for other converters, but Adobe Camera RAW ("ACR") has two profiles for every supported camera "built in" - one is generated from a target under "Illuminent A" lighting (2856 kelvin) (eg tungsten) and the other D50 or D65 (sorry, can't remember which off the top of my head) - the software can then interpolate between or extrapolate beyond these values to accurately simulate a wide variety of colour temperatures.

They adjust the temperature in a very interesting way ... part of the decoding process is to assign colorimetric data to the 3 (monochromatic) channels - so it needs colorimetric interpretation data (ie "what shade of red, green, and blue are the filters in my Bayer filter". What ACR does though is alter this colourimetric interpretation data to give a relatively lossless white balance adjustment (in essence with many ACR settings you're simply tailoring the conversion that's about to take place, rather than making multiple adjustments to the image which would be quite degrading).

If you're a glutton for punishment, grab a copy of Real World Camera RAW with Adobe Photoshop CS4 by (the late) Bruce Fraser and Jeff Schewe.

[DrJeans]

If you're a glutton for punishment, grab a copy of Real World Camera RAW with Adobe Photoshop CS4 by (the late) Bruce Fraser and Jeff Schewe.

Colin Southern, thanks for the link!
You can specify what is meant by: "If you're a glutton for punishment ..."?

[Colin Southern]

Colin Southern, thanks for the link!
You can specify what is meant by: "If you're a glutton for punishment ..."?

You're welcome.

Glutton for Punishment

[DrJeans]

You're welcome.

Glutton for Punishment

Colin Southern, I understand!
Russian saying: "trifle sick" or "meticulous"!

I've worked hard to repair electronic devices, setting up computers and computer programmer, so interesting to me all the details.