Monday, February 11, 2008

G9 and Raw

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Unlike most digicams, the Canon G9 can produce “raw” files. For many photographers, the ability to generate a raw file is one of the main reasons for selecting the G9. Even so, the usefulness and quality of raw vs JPEG is an ongoing debate and probably will always be an issue. As noted in other postings, JPEG is a very versatile and useful format. For the most part, the raw vs JPEG debate is really about the in-camera JPEG and its potential as compared to the raw – that is, unprocessed -- data from the sensor

If the in-camera JPEG produced by the G9 is analogous to using slide film then the raw image is analogous to using negative film. That’s why a raw file is sometimes referred to as a digital negative. Both negatives and raw files must receive further processing before a print can be made and those prints are highly customizable as well as highly dependent on the tools and skills of the user. This image, a crop from a previous illustration, is an example of an unprocessed raw file.

In comparison to the 8 bit JPEG, raw files are 16 bit data files; however, it turns out that all those bits are not actually used. For example, the Canon G9 produces 12 bit data files but places those in a 16 bit “wrapper”. Still, there is more information in a G9 raw file than in a G9 in-camera JPEG file. Although file size can be misleading (both are compressed), take a look at raw and JPEG files. Information has been discarded from the raw file in order to create the smaller JPEG file.

It is important to understand that the in-camera JPEG is made from the raw data in a second or two (and perhaps a fraction of a second) by the in-camera computer. The details of that JPEG -- tonality, contrast, saturation, sharpening, noise reduction, etc. -- were determined by a committee of marketers and engineers except for any tweaking that you toss in as in-camera options.

If your goal, whether in general or for a particular photograph, is to squeeze every possible pixel of quality from your camera, then you should shoot in raw mode and learn to process the raw data file.

My own preference is to shoot in raw mode and to process the raw file in Photoshop (more accurately Adobe Camera Raw – usually abbreviated as ACR). There are several other editing/conversion programs that will work with the G9 data files. Canon even includes some software, Raw Image Task (RIT) with the G9. Some of the other G9 raw image processors, include:

DCRaw is a command line program/module said to be the basis of many other programs
UFRaw provides a user interface to DCRaw and adds features
Bibble is more than raw conversion, includes other features such as noise reduction
BreezeBrowser is one of my most used tools, but it has not yet been updated for G9 raw files.

I don’t use any of the above programs for raw conversion except for ACR. In the next post, I’ll give examples of starting point settings in ACR for G9 raw files.

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3 comments:

ajc666 said...

Another excellent (if idiosyncratic) application for developing raw files is Silkypix, which also supports the G9.

Miguel said...

Also worth mentioning is Lightroom (although it uses ACR just like Photoshop). I currently own and use Lightroom but not Photoshop. If you don't do a lot of detailed retouching Lightroom is wonderful.

Gump said...

Gordon,

Great post on raw vs. jpeg and fantastic blog overall on the G9. I just purchased a G9 a week or so ago for a trip to Hong Kong (didn't want to take all of my heavy Canon glass) and have found your site extremely informative.

Really appreciate the information and insight. Thanks for sharing.

Adam
adamcb.smugmug.com