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I have some raw images captured using Canon,Nikon,Minolta cameras.(*.CR2, *.NEF, *.MRW)

I want to change resize them and store them back as the original format.

  1. I checked in two tools, Canon Digital photo professional and Adobe CS5, but could not find any resize option for raw images. Do they have it?

  2. How can I resize these images and store in same format as original file?

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Actually, RAW files aren't images but more something like data files. They contain the raw and unprocessed output of the sensor in your camera. –  Kristof Claes May 4 '11 at 20:39

3 Answers 3

up vote 17 down vote accepted

The entire point of raw files is to save the full unprocessed output of the sensor, there are no programs that edit raw files because if you do any editing it's no longer the raw output and you are better off generating a TIFF from the raw and editing that.

A note about resizing - most camera sensors have a pattern of red, green and blue pixels, where each pixel is only sensitive to a single color - the raw processing program (Adobe camera raw, lightroom, aperture, DPP, the built in camera software, etc.) takes that data and creates a picture where each pixel has 3 values (red, green and blue), as a side note, every software does it a little differently.

Resizing a raw would require generating a picture (using what software? with what settings?), resizing it and then trying to create a "raw" file that would generate the new resized image - after all this processing the new "raw" would have less accurate information that a TIFF (and probably even an high quality JPEG) - so I really don't see the point of going to all that trouble to write a very complicated algorithm that would only degrade the image quality.

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@If I open a CR2/NEF file in Adobe PS CS5, there is an option of Image size, where one can enter the new size(width,height,DPI) and it will resize the raw CR2/NEF image. –  goldenmean May 5 '11 at 11:06
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@goldenmean - no, when you open CR2/NEF file in PS there is an option of image size, when one can enter the new size and PS will process the data from the raw file (the data in the file is not an image - it's the camera sensor output that can be used to produce an image) and produce a new image in the desired size. –  Nir May 5 '11 at 19:37

You can't resize RAW files per se. You can crop them in a RAW editor like Adobe Camera RAW, and the crop information will be stored in the sidecar XMP file, but the RAW file itself remains the same.

This depends on your editor, but generally when you 'edit' a RAW file you are just storing settings in a 'sidecar' file. When you re-open the RAW file, the editor reads the sidecar file and reapplies the settings. The RAW file itself is untouched.

You can, however, save out a copy of the RAW file in a lossless format like TIFF, which you can 'properly' resize and edit however you like.

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DxO Optics can output processed photos as DNG files.

I'm not entirely certain what it is doing in the DNG file, but they certainly have something in them, since a 25 MB .CR2 somehow turns into a 75 MB .DNG.

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It will be storing three colours per pixel instead of 1. Raw files typically have one value either red green or blue per pixel as most sensors are monochrome devices. When you edit a file you typically have to interpolate the missing values. These interpolated values account for the 3x increase in filesize. Since DNG is based on TIFF I can't see the point of saving a three channel DNG instead of a TIFF! –  Matt Grum May 5 '11 at 7:53
    
Ah. Well, I had never tried outputting TIFF files from DxO or Aperture. If it's saving the Interpolated image, the filesize would make sense. I guess they must be saving the TIFF in 16 bit color depth, too. –  Fake Name May 5 '11 at 8:05

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