DCRAW, the Excellent
RAW conversion software
I have owned the Canon D60 dSLR since early 2003 and have faithfully been using the Canon bundled conversion software because is it an all-in-one solution and also because I have had the idea that the manufacturer would surely know better how the images from their cameras should be converted.
That was until I was introduced to the DCRAW in early 2004, and truly, I do not have words to describe how amazingly high quality RAW conversion software it is, below is one example (from this D60 CRW file) handheld and moving subject:
And another example, on tripod and steady subject:
The workflow for the above two versions in the two comparisons was exactly the same, with the obvious exception that both acquire paths have their own ICC profile. The editing steps were:
- Convert the CRW to linear 16-bit/c (by the Twain Acquire using Canon and by conversion to PSD using DCRAW.
- Assign the acquire path ICC profile.
- Convert to Working-space (CIE 1931 D65).
- Fine-tune the gray-balance.
- Levels adjustment (both black- and whitepoints)
- Sharpening (USM: A=300, r=0.5, T=0 ).
- Convert to nativePC for displaying on un-calibrated Windows machine.
And I can tell you that in what ever way the Canon converted version is post-processed in Photoshop it will not reach anywhere near to the DCRAW quality / sharpness.
The author of DCRAW Dave Coffin kindly provides this excellent free program as a C program source code, the DOS executables are provided by Francisco J. Montilla and speed optimized DOS executables for different CPUs by Benjamin Lebsanft. DCRAW converts RAW images from nearly 200 different digital cameras. The DCRAW is DOS software (until someone comes up with a good Windows user interface) but please do not close your eyes for it because of that. It can be easily used from many image viewers such as the excellent freeware software IrfanView by Irfan Skiljan you can download the tool from the DCRAW2PS page.
The DCRAW applies very high quality color-mask interpolation but the excellent appearance of the DCRAW converted image is only partly due to that, the interpolation of the color-mask-array is the key issue, Canon software and all the other 3rd party converters are using much larger spatial grid (kernel size) in the CMA (color mask array) interpolation, that is what results the unrecoverable blurred image.
I btw am one of those who have been repeating the old mantra: Only sharpen as the last step. This wisdom however dates back to the time when we only had scanners. Scanners do not have the color-mask-array (so the image data need no color-interpolation) and they do not have the so called anti-aliasing-fillter (a blur filter) on the optical path either. Digital cameras suffer from both these so a slight sharpening during the conversion indeed is beneficial just like the DCRAW show to us.
Yet another comparison example about the DCRAW quality (again the workflow was exactly the same for both versions less the ICC profile):
Some side comments: When using the Canon software there is absolutely no reason to buy the expensive L lenses, the most cheap objectives with their plastic lenses will do very nicely, the conversion software simply damages all sharpness that any lens can provide. And the various camera resolution tests would look pretty much different in case the DCRAW was used for the RAW conversion.
Some full size examples
Never seen before sharpness from a Canon D60, truly! Do not let IE to shrink the images. Click the below thumbnails to see the full 6MP version.
 10.4MB Jpeg (Quality 12) |
 6.7MB Jpeg (Quality 12) |
 8.0MB Jpeg (Quality 12) |
More about DCRAW:
DCRAW2PS launcher/linker tool for DCRAW, easly launch DCRAW conversion from within image viewer like the IrfanView and have the converted PSD to open in Photoshop automatically.
A comparison between VNG and AHD interpolation modes of DCRAW.
Accurate Image Manipulation for Desktop Publishing