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Old Jun 14, 2009, 6:11 AM   #1
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Default Question about RAW images

I am considering purchasing the Canon SX10 and installing CHDK to enable RAW images to be recorded.

I have never owned a camera with RAW capabilities before, and would like to know if a took a shot and applied certain settings like a scene mode or red eye reduction, would this be saved in the RAW image or would the 'unprocessed' image alone be recorded?
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Old Jun 14, 2009, 6:50 AM   #2
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The unproccessed image alone would be recorded.

But remember that many of the settings associated with a particular scene mode are camera settings like shutter speed and aperture, which affect the recorded RAW image as well.
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Old Jun 14, 2009, 9:35 AM   #3
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TCav is correct. The RAW image has not had any processing done to it and needs to have the settings applied by whatever RAW converter you use. Most of them, however, read the camera settings you have used, and will apply these as default when you do the conversion. The information is usually also stored with the processed image as part of the Exif data. (how much depends on the particular converter)

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Old Jun 14, 2009, 4:45 PM   #4
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Thanks for the replies.
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Old Jun 15, 2009, 7:53 AM   #5
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Camera manufacturers usually include a lot of information about camera settings in the metadata stored in an image (especially the proprietary information in the maker notes section of it).

A Camera manufacturer's raw converter may be able to apply some of these settings during the conversion to another format like jpeg or tiff (or let you change some of the settings as desired for the conversion).

However, as a general rule, third party raw converters (and the raw files generated by chdk are not supported by Canon) will only make use of the camera's "as shot" white balance settings (so they can apply the same RGB multipliers used by the camera when converting to another format).

That way, if the camera's white balance was correct, you don't have to spend time changing it later (and if it wasn't correct, then you can change it to something else using most raw converters). Other camera settings are usually ignored by most third party raw converters (although some converters will interpret portions the metadata so that you can see how some of your camera settings were configured).
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Old Jun 16, 2009, 8:24 PM   #6
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Originally Posted by matt20 View Post
...if a took a shot and applied certain settings like a scene mode or red eye reduction, would this be saved in the RAW image or would the 'unprocessed' image alone be recorded?
Yes and no.

The camera options (exposure mode, EV compensation, flash mode, ...) aren't part of any file. They control the way the camera works. The RAW-to-JPEG conversion settings (contrast, ISO, saturation, White Balance, ...) are saved in RAW files as header data but not processed into the image data.

Most external RAW conversion software ignores the settings stored in a RAW file's header with the general exception of ISO and sometimes WB. The only software that can make intellegent use of the other settings is generally the software supplied by the camera manufacturer since only they are privy to the internal working of the software code in the camera. Some 3rd party software attempts to apply their own equivalent adjustments based on camera specific conversion tables, but this is not a precise science. Their tables are derived from trial and terror experiments with the camera and not from any actual knowledge of how the camera itself would use the setting to process the image.

You'll need to research whether the CHDK hack saves the settings data the way models that ship with RAW capability do and whether that saved data makes sense to any external software. I would enter your project with the idea that it doesn't and that your RAW images will open in any RAW converter with only that converter's default settings. You can then simply apply your desired adjustments manually.
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