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Old Aug 23, 2009, 12:17 PM   #1
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Default Camera's Algorithms applied to RAW?

Scoping out for a new camera purchase and had a question about how cameras save their data.

Now that we're in the marketing friendly level of 10 and 12 megapixels for cameras, I'm going to guess that cameras rely more and more on algorithms of all shapes and sizes to clean up noise and other artifacts from the images.

Generally, do cameras apply some of these algorithms to the saved RAW image, or are they all applied only to the JPEGs or compressed formats?

If they don't I assume its a bigger task to finalize your RAW images. Or can cameras handle those megapixels without processing and I've just been away too long?
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Old Aug 23, 2009, 12:48 PM   #2
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Some manufacturers apply noise reduction to the raw files. For example, my Sony A700 does that (but, you can disable it with the latest V4 firmware if you'd rather the camera did not apply any noise reduction).

There is also evidence that some other manufacturers do the same thing. They just don't admit it. ;-)

As for other parameters (set in camera but not applied to the raw file), that depends on the raw converter being used. Camera manufacturers tend to store a lot of information about camera settings in the maker notes section of a raw file's metadata. Some raw converters can use this information if desired during the raw conversion process (with more support for settings usually coming from the camera manufacturer's converter).

Most raw converters can use the "as shot" white balance settings if you want them to. That way, you have a good starting point if you had white balance set correctly in the camera.
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Old Aug 24, 2009, 8:48 PM   #3
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And Nikon does apply some noise reduction to long exposure if enabled in the config.
But the Raw (NEF) file is as the sensor sees it no other modifications.
But beware that the embedded JPEG in the raw file has all the configured modifications applied, this is why sometimes the image you see in the small camera LCD is not exactly as the Raw file.

For my camera configuration I disabled all the modifiactions to JPEG to have an image as close as possible to the Raw image.
Except fot the in camera noise reduction on long exposure, there seem to be a concensus that the in camera NR is better than in PP.
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Old Aug 25, 2009, 6:04 AM   #4
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But the Raw (NEF) file is as the sensor sees it no other modifications.
Actually, there is evidence to suggest that Nikon applies a type of long exposure NR to raw files with some models (and it can't be turned off by camera settings).

http://www.astrosurf.com/buil/nikon_test/test.htm

There is also evidence to suggest that Nikon applies a type of NR processing to raw files from some models like the new D90, regardless of camera settings. Here's a discussion about it, using Rawnalyze to look at the raw data prior to the demosaic process:

http://forums.dpreview.com/forums/re...ssage=32401883

Dave Coffin (the author of dcraw.c ) noticed that Nikon was modifying raw data years ago. See question #12 from this interview with Dave in 2005:

http://www.dpreview.com/news/0504/05...ninterview.asp
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Old Aug 26, 2009, 8:58 PM   #5
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Interesting tests,
Thanks' for the links Jim
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