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Questions about "RAW develop" function

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Questions about "RAW develop" function
« on: 16 / April / 2008, 16:00:37 »
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As i understand, the camera "takes" a shot, but uses the RAW data from the file instead of taking new RAW data from the CCD.
I plan to use this function to process RAW's to JPG's on camera without use of further software, to create partial HDR's and clear long night exposures by using the average/sum functions, and get my final JPG.

If i develop a RAW-frame, and apply auto WB on camera settings, will the camera do WB from the developed RAW or will use the CCD RAW for it?
If it's the CCD data, then i'll have no use for this JPG as my final pic....
« Last Edit: 16 / April / 2008, 16:07:29 by thunderstorm »

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Offline GrAnd

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Re: Questions about "RAW develop" function
« Reply #1 on: 16 / April / 2008, 16:32:04 »
If i develop a RAW-frame, and apply auto WB on camera settings, will the camera do WB from the developed RAW or will use the CCD RAW for it?

That's good question. You can make the experiment: take one picture which requires, let say, fluorescent WB, and then develop it using AWB and directing the lenses to different light conditions (i.e. daylight, tungsten, etc).
CHDK Developer.

Re: Questions about "RAW develop" function
« Reply #2 on: 16 / April / 2008, 16:53:13 »
I was conducting a small experience.

1. I took a picture with RAW.
2. I developed the picture by "taking" a picture pointing once to a blue background and once to a red background.

The results were different white balances according to the background the camera was facing when the development shot was "taken".

I tought that maybe by taking the JPG+RAW using daylight WB, and then use daylight when developing i'll get same WB, but even then, i think, the camera still applying different WB according to what it see.
(BTW - Daylight stands for same R, G, and B, right?)

So perhaps the only solution is to immediatly develop the processed RAW (after merging), keeping the camera on the tripod facing the same direction. It will only work for long night exposures where nothing changes in matter of minutes.

Maybe there is a way to tell the camera to do WB from the developed RAW, or to add such a code to the chdk ? :)

It could be really useful for people like me, since i don't trust my eyes or CRT-monitor to do WB by myself after downloading.
(I know i can use one of the JPG's for WB, but i'm looking for a solution on-camera).
I want to download the "final product" from it and to use it's own excellent engineered WB capabilites, if possible.
« Last Edit: 16 / April / 2008, 16:58:36 by thunderstorm »

Re: Questions about "RAW develop" function
« Reply #3 on: 16 / April / 2008, 17:00:00 »
And one more thing. I noticed that in one of the RAW pictures i took, the time stamp on the file was way off... it said 15.4.08 02:30 when it was 16.4.08 23:30....

Is it a bug, or it supposed to be this way?


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Offline PhyrePhoX

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Re: Questions about "RAW develop" function
« Reply #4 on: 16 / April / 2008, 17:01:50 »
hm i never use auto-wb. in theory, when you take the pictures in daylight WB setting, developing the raw with daylight WB should have the same output? hm, will make tests regarding this tomorrow.

Re: Questions about "RAW develop" function
« Reply #5 on: 16 / April / 2008, 17:24:56 »
hm i never use auto-wb. in theory, when you take the pictures in daylight WB setting, developing the raw with daylight WB should have the same output? hm, will make tests regarding this tomorrow.

Yep, it works.
By using daylight WB, both for the real shooting (JPG+RAW), and then using it too for developing, it doesn't matter where you point the camera to, you get the same WB! :)

I pointed it once to a red background, and then to a purple background. Seems identical!
I'll be happy if other people tests this too.

You say you never use auto-WB?
It does makes common sense when you picture outdoors, and in fact... i think, maybe i'll use daylight-WB always, since it creates a picture with it's real color-temp as our eyes see it in the moment of the capture, right?
It applies to tungsten lights (when you want people to remain "yellowish", just like you see them for real in that light), or for long exposures at night when you want to keep the beautiful color tone of the city lights.

Re: Questions about "RAW develop" function
« Reply #6 on: 16 / April / 2008, 18:27:14 »
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« Last Edit: 22 / April / 2008, 18:03:17 by Barney Fife »
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Re: Questions about "RAW develop" function
« Reply #7 on: 17 / April / 2008, 05:53:34 »
What about applying Daylight WB for both?
Wouldn't daylight WB would be eq as shooting with 35mm film that has no ability for WB in post-processing?
I mean, using daylight WB means to keep the true scene colors as they are.. if it's tungsten light than all the faces will be warmer, just like we see them for real.
Daylight also means that all R, G, and B, are at the same level. No different levels between them.

Am i correct? :)


Re: Questions about "RAW develop" function
« Reply #8 on: 17 / April / 2008, 05:54:18 »
R,G,B in the transform matrix of course... (not in whole picture)

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Offline PhyrePhoX

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Re: Questions about "RAW develop" function
« Reply #9 on: 17 / April / 2008, 06:19:37 »
You say you never use auto-WB?
It does makes common sense when you picture outdoors, and in fact... i think, maybe i'll use daylight-WB always, since it creates a picture with it's real color-temp as our eyes see it in the moment of the capture, right?
It applies to tungsten lights (when you want people to remain "yellowish", just like you see them for real in that light), or for long exposures at night when you want to keep the beautiful color tone of the city lights.
auto-things always work ok. but ok is not enough, is it. when you KNOW you are inside, then you KNOW that there isnt much daylight, at least from the evening to the morning (hey, i just got an idea: how about setting WB automatically to NOT_DAYLIGHT when out of defined timezone... well, just an idea :D) so you can set it to artificial light.
and no, you can not leave the setting on daylight - people should look always the same, be it in daylight or candle light or tungsten light (okay, they do look different in different light, but not that much) - for the camera though things look WAY different. thats why you should set WB as often as possible according to given situations.

 

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