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Old May 20, 2007, 9:08 AM   #1
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Hello All,

I recently downloaded the HACK for my Canon A640 which now enables me to shoot RAW.

How do I manipulate these pics in Photoshop? Would someone please explain the steps as simply as possible? I'm attempting to use this DNG Camera RAW program to convert the files to DNG - Then they're supposed to go through another step and program to process prior to Photoshop???

Please help - Thanks - John
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Old May 20, 2007, 1:54 PM   #2
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What version of photoshop do you have?
We can't give you precise instructions without that info.

If you can convert the image to DNG, then you just need the proper version of PS and then open the file. It will open a dialog that lets you adjust the image and then click OK. When you do that, it will open in PS.


Eric
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Old May 21, 2007, 10:20 AM   #3
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Thanks Eric. I have PS version 7.0 When I attempt to open the Digital Negative file with PS it (the file) doesn't even apper in the 'open' window - not an option.

If you know an easier way to convert to DNG, I'd appreciate that as well.

Thank you - Ponz
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Old May 21, 2007, 10:46 AM   #4
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Sorry, you'll need a newer version of Photoshop to process .dng files.

Camera Raw Version 2.4 will work with Photoshop CS and it can process your .dng files

Camera Raw Version 3.1 (or any higher 3.x) version will work with Photoshop CS2 and it can process the .dng files.


Camera Raw 4.x versions will work with Photoshop CS3 and it can process the .dng files.

http://www.adobe.com/support/downloa...atform=Windows

No support for .dng files is available from Adobe for Photoshop Version 7.

You can also process .dng files using newer versions of Photoshop Elements (3, 4, 5) with newer Camera Raw Plugins downloadable from Adobe.

There are a number of third party raw converters that will work with .dng files. So, you may want to try one of those to convert your images into a format that your version of Photoshop can use (TIFF or JPEG).

Give UFRaw a spin. It supports .dng and it's free:

http://ufraw.sourceforge.net/


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Old May 21, 2007, 11:00 AM   #5
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P.S.

I'm assuming that you're already using the correct converter to convert your raw files into .dng format for use by raw converters that support .dng..

You'll need to use the dngtopowershot conversion program mentioned in this wiki to do that part.


FAQ on processing RAW images from Powershot Models using this hack


IOW, it will be a two step conversion (one to get the images into .dng format so that raw converters that support .dng can process them), another to convert from .dng to a usable image format like jpeg for browsers, printers, etc.).

Note that dcraw.c has native support for your Powershot A640's raw files now.

Many raw converters use some or all of Dave's Code. So, you'll start seeing more of them support the files from your camera directly in the future (no need to convert to .dng first). UFRaw is one example of that (uses dcraw.c for the base raw conversion engine). But, it's based on a March release of the dcraw.c code (and your camera model probably wasn't in it yet). You may want to give it a try anyway, since I'm not sure when this model was added to Dave's code (Dave Coffin's dcraw.c code that UFRaw is using).

But, chances are, you'll need to convert to .dng first to use it (I think the A640 was added later than the other A6xx models using the hack).



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Old May 21, 2007, 3:12 PM   #6
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Jim,

"So, you may want to try one of those to convert your images into a format that your version of Photoshop can use (TIFF or JPEG)."

Wouldn't that defeat the purpose of shooting RAW to begin with?

"I'm assuming that you're already using the correct converter to convert your raw files into .dng format for use by raw converters that support .dng.."

I'm using that dng4ps 1.1.4d - but I must say it's quirky at best. It seems to freeze, then all of a sudden it will say process complete.

Let me see if I fully understand this process:
  1. Camera shootds RAW (a few extra pixels and zero correction[/*]
  2. RAW file is then converted to dng[/*]
  3. What is meant, exactly, by dng files being processed? Into what? Manipulated like jpeg, or tiff? Then 'saved' as a jpeg or tiff?
[/*]
I'd love to read a tutorial somewhere.

Thanks a BUNCH!

Ponz




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Old May 21, 2007, 3:36 PM   #7
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.dng is a raw format. Basically, it's acting as a "container" for your camera's raw files.

The raw file produced by a given camera model is somewhat unique, and a complicated process is needed to convert the image into a viewable format (and diffferent raw converters will have different approaches to giving you the best image possible, with some of them using better algorithms compared to others for this conversion). So, you have to use a raw converter that supports your camera's unique files, or convert them into a format that is understood.

A camera's image processing when shooting jpeg is making decisions that may not always be what you want.

Manufacturers have to decide on what kind of tone/contrast curves to use to make an image that looks good to most viewers, and sometimes they use processing that can be a bit too contrasty (causing loss of detail in shadows and highlights), in order to give cameras owners a more "punchy" image straight from the camera.

Ditto for things like sharpening, which is mostly increasing the contrast at color/brightness transitions in an image using edge detection techniques (which can destroy detail if overdone). The same thing is true for how the camera compensates for the temperature of the lighting you're shooting in (your White Balance settings handle that). You can easily modify things like White Balance later if you shoot in raw.

The camera's jpeg processing is also limited by the speed of the cpu/hardware for image processing built into the camera, as to the sophistication of the algorithms used, since they are trying to process images in a split second between shots.

As a result, you can usually do better if you shoot in raw, using a high powered PC to processs the data from the camera's sensor, without the limitations of needing to process it in a split second that the camera's image processing has to deal with.

The individual photosites in a sensor are only sensitive to one color each, and with most Bayer Pattern CCD designs, you have twice as many sensitive to green.

The raw conversion algorithms take the values from the red, green, and blue photosites and combine them via sophisticated interpolation techniques so that all 3 colors are stored at each pixel in order to give you a usable/viewable image.

The raw file has not combined the photosites in any way.

That's what the raw conversion process does (or in camera processing if you shoot in jpeg). There are a number of different algorithms used, and some are better than others. You can see some of the common ones discussed here (requires Adobe Acrobat Reader):

http://www.ece.gatech.edu/research/labs/MCCL/pubs/dwnlds/bahadir05.pdf

Here is another document discussing raw conversion techniques:

http://www.dalibor.cz/files/Ting%20C...erpolation.pdf

When you convert to TIFF using a raw converter you've gone through this demosaic process of combining the values from the red, green and blue sensitive photosites so that red, green and blue are stored at each pixel location. Ditto for shooting in jpeg (the camera is performing the raw conversion if you shoot jpeg) and you can also convert a raw image to jpeg using most raw converters.

Most raw converters are doing some additional processing, too (sharpening, contrast, etc.). Ditto for in camera processing (which is doing the raw conversion for you).

Personally, I'd save the raw files, no matter your preference in raw converter, as technology is continuing to improve and you may want to reprocess cherished images later using better tools.

For example, b
eginning with dcraw.c version 7.60, David Coffin started using AHD (Adaptive Homogeniety Directed) for the interpolation algorithms.

This was in part due to Paul J. Lee, whocollaborated with Hirakawa Keigo (the original co-author of AHD algorithm as part of his Ph.D thesis).

Once Paul fully understood the algorithm,he modifieddcraw.c to use it and gave a prototypeto Dave. After some comparison studies, Dave was convinced that AHDwas superior to VNG and other demosaicing algorithms.

Dave converted and optimized the prototype created by Paul J. Lee, integrating it into dcraw.c versions 7.60 and later (he's continuing to refine it).


So, products using some or all of David's code to perform the raw conversion also benefit from these improvements, while adding their own enhancements and features.

A number of other raw converters use some or all of David's source code for the demosaic part, while adding a GUI front end and more features to augment the conversion algorithms.

See the "Other Raw Photo Decoders" section here:

http://www.cybercom.net/~dcoffin/dcraw/

UFRaw (mentioned in my earlier post) is one popular free product that uses Dave Coffin's code for the demosaic algorithms. At some point in the future (if it can't already) it will support your camera without any conversion to .dng, since Dave Coffin's newer dcraw.c code now supports your camera model.

The only reason you need to use the raw to dng convertor for your camera at all, is because your camera's native raw file format is not supported by most current raw converters, other than dcraw.c or converters that use it's newer versions for raw conversion.

So that you can use your camera's raw files with more raw converters, a programmer wrote a program (the one you're already using) that converts it's raw files into different raw image format (Adobe .dng) that is supported by some of the popular raw converters like Adobe Camera Raw 2.x or later (not available for your older version of Photoshop).

But, to get the raw file (either native or .dng) into a usable, printable image, it needs to be converted to another format that has already gone through the demosaic process (for example, TIFF or JPEG), combining values for red, green and blue at each pixel location. That's where a raw converter comes in (Adobe Camera Raw, UFRaw and many more).


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Old Jun 9, 2007, 2:01 PM   #8
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Hello Again,

I'm giving Adobe CS3 (Master Collection)- Photoshop a free trial. If I understand the HELP files correctly, I need to use Bridge as well

I have installed the hack on my Canon A640. It creates a file named "CRW_190"

Photoshop does not recognize it. Would someone please give me a quick "How to open and manipulate RAW 101" course. Really down and dirty. I just need a small jump start.

Thanks! - Ponz
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Old Jun 9, 2007, 2:08 PM   #9
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See my previous post in this thread. Photoshop (even CS3 using the very latest Adobe Camera Raw plugin) is not going to recognize native raw files from your camera. The native raw files generated by the "hack" you're using are not supported by Adobe. You'll need to convert them to .dng using a special conversion program first.



JimC wrote:
Quote:
P.S.

I'm assuming that you're already using the correct converter to convert your raw files into .dng format for use by raw converters that support .dng..

You'll need to use the dngtopowershot conversion program mentioned in this wiki to do that part.


FAQ on processing RAW images from Powershot Models using this hack


IOW, it will be a two step conversion (one to get the images into .dng format so that raw converters that support .dng can process them), another to convert from .dng to a usable image format like jpeg for browsers, printers, etc.).

Note that dcraw.c has native support for your Powershot A640's raw files now.

Many raw converters use some or all of Dave's Code. So, you'll start seeing more of them support the files from your camera directly in the future (no need to convert to .dng first). UFRaw is one example of that (uses dcraw.c for the base raw conversion engine). But, it's based on a March release of the dcraw.c code (and your camera model probably wasn't in it yet). You may want to give it a try anyway, since I'm not sure when this model was added to Dave's code (Dave Coffin's dcraw.c code that UFRaw is using).

But, chances are, you'll need to convert to .dng first to use it (I think the A640 was added later than the other A6xx models using the hack).
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