Discussion in 'Beyond the Basics' started by PhilGarber, Sep 21, 2008.
What does it mean to shoot in RAW? What are it's pros and cons?
While I would be happy to share what I've learned about it, you'll find much more information than I could ever provide by doing forum and google searches. The pros and cons of raw are endlessly debated and there's tons of information out there.
Shooting in RAW allows you to alter the final image in post. You can correct white balance and exposure (to a degree) as well as other settings. Of course you need to have a software program such as Photoshop or Lightroom to take advantage of RAW files.
Below is a technical explanation of RAW files for you.
RAW (AKA Raw Image File) is a file that contains unprocessed data as captured by the sensor of a digital camera. This allows the user to process the image to their liking using a RAW image converter at a later point in time as a JPEG, TIFF or other file format of their choice.
RAW files are not a standard. They differ from manufacturer to manufacturer and even from camera model to camera model.
Therefore RAW Conversion Software must be updated and adjusted for each and every new camera that should be supported.
The structure of a RAW file is that individual pixels are monochrome i.e. only bear one color (in contrary to most other image files where each pixel consists of a color resulting from three - RGB - or four - CMYK - sub-pixels).
This is a direct result of the sensor's design, using light receptors that bear a color filter.
In most of the current digital cameras it is a matrix of RGGB pixels with twice as much green pixes as red and blue (contributing to the human eye's high sensitivity to green).
Calculating a full color pixel out of several adjacent monochrome pixels is called de-mosaicing, the pattern in which the RGGB pixels are arranged is called Bayer-Pattern. Thus de-mosaicing is often also called Bayer interpolation.
The nature of a RAW file consisting only of monochrome pixels is the reason for RAW files' relative small size (~8 MB for a compressed 10 megapixel file).
Most cameras can save RAW files either uncompressed or with a so-called lossless compression.
Each manufacturer has their own proprietary RAW format. Adobe as made a push to have all manufacturers (Leica is using it in the DMR-series cameras) use a common format, DNG, which was developed by Adobe and in the public domain. Here are some of the more common RAW formats:
DNG - Adobe - Digital NeGative
NEF - Nikon- Nikon Electronic File
CRW - Canon - Canon RaW
CR2 - Canon - Canon Raw 2
X3F - Foveon
MRW- Minolta - Minolta RaW
ORF - Olympus - Olympus Raw Format
PEF - Pentax - PEntax Format
SRF - Sony - Sony Raw Format
SR2 - Sony - Sony Raw 2
ARW- Sony - Sony RaW
RAF - Fuji - RAw Fuji
RAW/TIF/TIFF - used by several companies as their raw format
DCR - Kodak
KDC - Kodak
KPDC - Kodak
Thanks guys! That was helpful!
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