gvarner wrote:
And so I looked it up to learn more. Per Wikipedia, "Normally, the image is processed by a raw converter in a wide-gamut internal color space where precise adjustments can be made…" and then it’s converted to JPEG or TIFF or whatever format you want for the final product. So it’s initially converted to something that can be viewed and edited and then to other formats for further editing or printing.
All image files are converted to something that can be viewed by some program. Canon's raw files and their DPP program are proprietary and what they do is a secret. But I think it is incorrect to assume that "it’s initially converted to something that can be viewed and edited." I don't see that phrase in the Wikipedia article. The files need to be converted to some other format only so that other programs can read and display them. But there is no inherent reason why raw files could not themselves be the "final product."
Later in the article you will find this:
"Many raw file formats, including IIQ (Phase One), 3FR (Hasselblad), DCR, K25, KDC (Kodak), CRW CR2 CR3 (Canon), ERF (Epson), MEF (Mamiya), MOS (Leaf), NEF (Nikon), ORF (Olympus), PEF (Pentax), RW2 (Panasonic) and ARW, SRF, SR2 (Sony),
are based on the TIFF file format."
That strongly suggests that raw files are not so radically different from other image file formats. My guess (and we can only guess) is that what DPP is displaying when you open a raw file is much more likely a TIFF file variant rather than to a JPEG file (it is most certainly is not a JPEG). Many programs can display TIFF files. Why can those programs not display a Canon raw file? Because Canon is intentionally preventing that to force you into their system, as are the other manufacturers. Maybe the manufacturers are response for all of the ideas people have a about raw files being some sort of magical "negative" that "can't be viewed" without their special software, or without extensive difficult and time consuming "processing."
And then there is this about the proprietary (and monopolistic) nature of raw formats:
"Different manufacturers use their own proprietary and typically undocumented formats, which are collectively known as raw format. Often they also change the format from one camera model to the next. Several major camera manufacturers, including Nikon, Canon and Sony, encrypt portions of the file in an attempt to prevent third-party tools from accessing them."
And then there is this about why that is a problem:
"This industry-wide situation of inconsistent formatting has concerned many photographers who worry that their valuable raw photos may someday become inaccessible, as computer operating systems and software programs become obsolete and abandoned raw formats are dropped from new software. The availability of high-quality open source software which decodes raw image formats, particularly dcraw, has helped to alleviate these concerns. An essay by Michael Reichmann and Juergen Specht stated "here are two solutions – the adoption by the camera industry of A: Public documentation of RAW [sic] formats; past, present and future, or, more likely B: Adoption of a universal RAW [sic] format". "Planning for [US] Library of Congress Collections" identifies raw-file formats as "less desirable file formats", and identifies DNG as a suggested alternative."
This statement in the Wikipedia article is misleading, I think:
"Cameras that produce raw files save these settings in the file, but defer the processing. This results in an extra step for the photographer, so raw is normally only used when additional computer processing is intended."
This is simply not true in my direct experience.
Later, under "drawbacks" there is this:
"The time taken in the image workflow is an important factor when choosing between raw and ready-to-use image formats. With modern photo editing software the additional time needed to process raw images has been greatly reduced but it still requires an extra step in workflow in comparison with using out-of-camera JPEGs."
Sure. It is an "extra step" - what, like 5 seconds? - if JPEGs are all you want. Back before digital cameras we scanned prints into a lossless format, and then sized, edited and as the very last step converted to JPEG. That was not a big deal then, and it is not a big deal now. Conversion to JPEG is the least of the worry and the quickest and easiest step imaginable. The idea that allowing the camera to convert images to JPEGs is somehow saving anyone some great amount of time or effort is just nonsense in my opinion.
In my experience, the workflow is much faster working with raw files than it was working with JPEGs. "Processing??" "Converting??" Click, done. I am not saying that this will be true for everyone, nor am I suggesting that there is no place for using JPEG files.
And then we have the benefits of working with raw files:
* Many more shades of colors compared to JPEG files - raw files have 12 or 14 bits of intensity information per channel (4096-16384 shades), compared to JPEG's gamma-compressed 8 bits (256 shades).
* Higher image quality. Because all the calculations (such as applying gamma correction, demosaicing, white balance, brightness, contrast, etc...) used to generate pixel values (in RGB format for most images) are performed in one step on the base data, the resultant pixel values will be more accurate and exhibit less posterization.
* Bypassing of undesired steps in the camera's processing, including sharpening and noise reduction
* JPEG images are typically saved using a lossy compression format (though a lossless JPEG compression is now available). Raw formats typically use lossless compression or high-quality lossy compression.
* Finer control. Raw conversion software allows users to manipulate more parameters (such as lightness, white balance, hue, saturation, etc...) and do so with greater variability. For example, the white point can be set to any value, not just discrete preset values like "daylight" or "incandescent". Furthermore, the user can typically see a preview while adjusting these parameters.
* The color space can be set to whatever is desired.
* Different demosaicing algorithms can be used, not just the one coded into the camera.
* The contents of raw files include more information, and potentially higher quality, than the converted results, in which the rendering parameters are fixed, the color gamut is clipped, and there may be quantization and compression artifacts.
* Large transformations of the data, such as increasing the exposure of a dramatically under-exposed photo, result in fewer visible artifacts when done from raw data than when done from already rendered image files. Raw data leave more scope for both corrections and artistic manipulations, without resulting in images with visible flaws such as posterization.
* All the changes made on a raw image file are non-destructive; that is, only the metadata that controls the rendering is changed to make different output versions, leaving the original data unchanged.
* To some extent, raw-format photography eliminates the need to use the HDRI technique, allowing a much better control over the mapping of the scene intensity range into the output tonal range, compared to the process of automatically mapping to JPEG or other 8-bit representation.
The article is pretty good, I think. Thanks.
Mike