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Old Feb 14, 2006, 7:32 PM   #1
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Repairing under-exposed RAW photos is easy, but so is repairing OVER-exposed RAW photos quite often. Much data in a RAW OVER-exposed photograph is often retained and its amazing how much detail can be re-gained in a good RAW editor. (Nothing like shooting JPEG because the data is compressed in JPEG and thats all you get.)

Also, keep your GOOD raw pics even after you edited them. Sometime down the road you might say "What was I thinking???" and want to start editing it/them over again. Learned the hard way here... :?

Wayne B.
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Old Feb 14, 2006, 8:33 PM   #2
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Hey Wayne,

My understanding of RAW is the edits are non-destructive.

I always shoot RAW with my 20D.

Sometimes it's a bit of a pain to deal with RAW, but the benefits outweigh the hassles!

-- Terry

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Old Feb 20, 2006, 6:36 PM   #3
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you are absolutely correct. since i made the decision to go totally raw i've never looked back.. altho you can fix some pretty big blunders it also makes you think more about the shot.

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Old Feb 25, 2006, 2:38 AM   #4
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Hopefully you guys can provide me with a little help.....I understand RAW and all of its features, benefits. I don't understand the advantage of shooting RAW and JPEG together. Anyone care to shed a little light for me?
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Old Feb 25, 2006, 6:36 AM   #5
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Adding a jpeg to a raw image makes previewing much faster and better. To view a raw image you have first to interpolate for each pixel of the Bayer mosaic the two missing colors. This is called demosaicing. There are many different demosaicing algorithms. The in camera demosaicing algorithms have to be quite simple and therefore are low quality. That's why you can gain more detail from raw images. Unfortunately the implementations of the demosaicing are very inefficient (look at dcraw.c). The don't use Intel extremely powerful SSE/SSE2 instruction unit (the AMD version is not competitive). Using it full resolution, low quality demosaicing of a an 8 MP image could be performed in fractions of a second. I have a high quality demosaicing algorithm, which is also SSE2 capabable. In the second step the linear 12 bit CCD information has to be transformed into nonlinear 8 bit colors suitable for the human eye. This transformation also uses the cameras white balance information. While this transformation canot be done with SSE/SSE2, it is fairly simple and already quite fast now. Nevertheless both of my viewers, Fastone's Maxviewer and Irfanview do a bad job as far as colors of raw images are concerned. Irfanview seems to use dcraw.c, whence demosaicing is very slow. The Maxviewer is much faster but uses a low quality algorithm with 1/4th of the resolution. That's why an imbedded jpeg is much faster and better for previewing.
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Old Feb 25, 2006, 7:27 AM   #6
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I agree with kassandro - or at least as much of whatI understand he said. Glad to see some knowledgeable technical folk commenting on what is really going on inside the camera. Figure if I see that kind of technical stuff fairly frequently, a little bit of it just might sink in.

With RAW+JPEG using 11Mbytes/image, the first thing I do after downloading is some heavy deleting. If you do not load IrfanView's RAW plug-in,the thumbnail viewerloads fast, showing the RAW images as an icon. With the thumbnail size set as large as possible, a good first cut can be made quickly. For closer delete/keep calls, the full JPEG can be viewed simply by double clicking. Just have to remember to delete both the JPEG and RAW version of the same image.
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Old Feb 26, 2006, 2:41 AM   #7
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Thanks for the info!
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