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08-14-2007, 03:28 PM   #1
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K100d is RAW really RAW?

I had always assumed that Raw was the unaltered data the sensor recorded and that white balance and other settings didn't matter. While out shooting today I took a photo with AWB and then followed it with one shot on shade just for the hell of it. In LR I converted to Jpeg using the daylight preset, the same numbers for each image, 5500, +10. Look at the difference.

AWB-->daylight



Shade-->daylight



Has anyone else noticed this kind of behaviour? It appears thatt WB is being applied to the RAW data before being saved as a PEF.

08-14-2007, 04:30 PM   #2
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I always thought that the camera would expose the way you tell it to in raw, but that in post processing, you could make adjustments to wb, etc. Not sure there is a default setting...
08-14-2007, 08:36 PM   #3
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You might try converting them using Pentax Photo Lab (just this once) to see if the software makes a difference.
08-14-2007, 08:43 PM   #4
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I've finally gotten gimp working properly on my machine, and I was surprised how easy to use their raw plugin is, and how efficient it appears to be.

And the best part.... It's Free

08-14-2007, 08:51 PM   #5
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A RAW image contains unaltered data from the sensor, but the actual shot WB setting is recorded too. That is why you see an "As shot" setting in LR. From the two images, something must have changed, like a cloud or something else that made the jump. Or you just won't let the Auto WB setting to settle before taking the second image. Maybe you moved your camera away from the scene, WB changed, then came back but had the old WB setting active.
Just my .2 cts.
08-14-2007, 09:03 PM   #6
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I believe the temperature settings are saved with the PEF. I use SilkyPix for PP raw development. I can change the WB in camera so that my screen previews look correct while I'm shooting. If I took a one shot in AWB under incandescent lights then change the in camera WB to incandescent for the second shot I can open them both in SilkyPix, set the temperature for the first shot to match the temperature of the second shot and they'd be identically white balanced. I think raw is raw and what pentax has done is allowed WB info to be saved in the pef file so that any previews look correctly white balanced.

Chuck
08-14-2007, 09:53 PM   #7
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Steve, I have noticed with my *istD that occasionally one single shot will be completely off colourwise, and next to impossible to fix in ACR, and all the other shots are just perfect. I've never figured why. You should probably do a few shots at each setting before concluding anything.
08-14-2007, 10:15 PM   #8
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It appears that for at least some cameras (K100d, DS etc.) Pentax appears to apply WB to RAW data before saving.

UFRaw - Contribute

I tested this out using my camera on Daylight WB and instead of yielding the same value (5200k or whatever) each one was a little bit different.

some RAWs are not clear RAW | OpenRAW
Adobe Forums - White Balance in LR vs. Aperture

My above example and several other tests seem to reveal this. I am not a measurebator and this problem has a simple workaround but it IS curious.

08-14-2007, 11:40 PM   #9
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Hi Steve

I have noticed this as well on my k100d. the white balance setting remains as set by the camera unless i change the color temperature.

Thanks for posting the question, i didnīt consider it til now.

Regards
08-15-2007, 05:38 AM   #10
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The answer is quite simple ...

RAW is RAW - and the camera does nothing to it.

BUT..... when shooting RAW - the camera DOES calculate WB and adds the data to the RAW file. Look at the EXIF data of a RAW file and you'll find lots of info like this.

When the RAW file is loaded into the RAW converter (at least those I checked) - then, depending on the software setting, the software may use the EXIF data to convert the RAW file. Generally you can change this behavior per file or in some preferences setting.
08-15-2007, 06:43 AM   #11
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QuoteOriginally posted by ben-pentax Quote
RAW is RAW - and the camera does nothing to it.

BUT..... when shooting RAW - the camera DOES calculate WB and adds the data to the RAW file. Look at the EXIF data of a RAW file and you'll find lots of info like this.

When the RAW file is loaded into the RAW converter (at least those I checked) - then, depending on the software setting, the software may use the EXIF data to convert the RAW file. Generally you can change this behavior per file or in some preferences setting.
Actually it seems that this is not the case w/ Pentax (models unknown. All?)
"They noticed WB adjustment results differed a lot in Pentax own software and ACR, dcraw, UFRaw.
This leaded to suspicion WB settings are already applied to the RAW file. They wrote a program to extract data from RAW and show channel histograms. It happened RAW files shot with different WB settings differed not only in exposures, but in channels.
* AWB: http://img89.imageshack.us/img89/7518/imgp9705pefsrl2.jpg
* Daylight WB: http://img291.imageshack.us/img291/9208/imgp9706pefszp6.jpg
* Tungsten WB: http://img149.imageshack.us/img149/3917/imgp9707pefssi3.jpg
* Manual WB (grey card): http://img148.imageshack.us/img148/3273/imgp9708pefsff4.jpg

So it is the fact now - Pentax applies WB to RAW data"
May need more verification though.
BUT this is not as bad as what Minolta seems to do.....
"Minolta/Sony camera RAW results depend on the colour space of the shot. It can only happen if colour space conversion is applied before written RAW data.

Canon has its own RAW suspicions."
Nikon most likey not...
White Balance Redux

SEEMS this is an old topic.... DS also applies WB prior to saving RAW...I'll have to browse more of this thread.
Unequivocal evidence: Pentax SLR Talk Forum: Digital Photography Review

Last edited by jeffkrol; 08-15-2007 at 07:01 AM.
08-15-2007, 08:19 AM   #12
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I think all manufacturers do that. They have the RAW data from the sensor but take into account the WB setting of the shot and save it in the EXIF. Is a prerogative of the Raw converter to use this data or simply do it's own calculations.
08-15-2007, 08:21 AM   #13
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It seems every company has its 'issues;. Canon applies some hardware based NR to its RAW files, Sony and Pentax have the above mentioned issues. Nikon doesn't doctor their files but does have the encrypted WB issue and also uses a compression algorithm that discards some highlight detail on its compressed NEF files.

You can't win it seems.....I wish these companies would just come clean with this kind of thing so we as comsumers could make better choices/ This WB discovery has thrown my workflow into dissaray (well just a bit) as I try to sort out the best WB for attaining neutral results.
08-15-2007, 08:56 AM   #14
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QuoteOriginally posted by arbutusq Quote
It seems every company has its 'issues;. Canon applies some hardware based NR to its RAW files, Sony and Pentax have the above mentioned issues. Nikon doesn't doctor their files but does have the encrypted WB issue and also uses a compression algorithm that discards some highlight detail on its compressed NEF files.

You can't win it seems.....I wish these companies would just come clean with this kind of thing so we as comsumers could make better choices/ This WB discovery has thrown my workflow into dissaray (well just a bit) as I try to sort out the best WB for attaining neutral results.
All digital cameras convert analog information (light patterns and colors) to a digital file. The sensor in the camera is essentially an analog device, converting light to (analog) electrical impulses. The camera uses an analog to digital converter to convert the electrical impulses to digital form and produce the digital data file containing the image. So all digital cameras apply digital image processing to the output, whether the output is "RAW," .jpeg, or any other format. The idea of "RAW" files is that the "minimum" processing is done in the camera, to allow you to have more control in processing the image in the computer. But the image file cannot be completely unprocessed, even in a RAW file.

I don't think that the camera companies are concealing anything in terms of RAW files; the design compromises imposed by technical and economic limitations are going to result in quirks and imperfections in the product. The one exception is Nikon's encryption of the white balance data. It seems that the only reason for this is to compel Nikon users to buy Nikon Capture rather than a competitor's product.

There do seem to be some quirks in how Lightroom is processing the white balance of the Pentax files with it's own color balance pre-sets, but you can use the custom balance to get the shots to look they way you want. FWIW, I think the Pentax Photo Lab program actually does a better job with RAW processing than Lightroom, but Photo Lab has limitations in other respects.
08-16-2007, 04:33 AM   #15
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QuoteOriginally posted by arbutusq Quote
It appears that for at least some cameras (K100d, DS etc.) Pentax appears to apply WB to RAW data before saving.
I am quite sure that this is NOT the case. The camera saves the colour temperature value, whether it is an AWB determined or preset but it does nothing to the RAW data in the RAW file, that is, only the saved colour temp value is different and all else are equal.

QuoteQuote:
My above example and several other tests seem to reveal this. I am not a measurebator and this problem has a simple workaround but it IS curious.
I'm a measurbator but I have never encountered the case that the WB setting with a PEF RAW file generated from my K100D could not be overriden. :-) At least this is true for the original Photo Lab. So, it would be most likely to be a software issue for your case afterall. Btw, which RAW convertor did you use?
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