Output image file quality / JPEG artifacts
Standard Test Scene
Below you will find crops of the same 240 x 180 portion of the center of a sequence of images taken at some of the available combinations of image size and quality. Crops shown are at 100%, saved as extremely high quality JPEG. The RAW file was converted to a TIFF using Canon RAW Image Task 2.0.1 via ZoomBrowser EX.
|3504 x 2336 RAW (Uncompressed)
10,326 KB .CR2 (not for download)
|3504 x 2336 (L) JPEG Fine
2,968 KB .JPG
|3504 x 2336 (L) JPEG Normal
1,500 KB .JPG
|2544 x 1696 (M) JPEG Fine
1,733 KB .JPG
1728 x 1152 (S) JPEG Fine
As we may expect (as this camera has the same image processing as the EOS 20D - DIGIC II) the results are almost identical. Fine JPEG mode delivers very clean images with no detectable artifacts. Images (at Large size) that are in fact very difficult to distinguish from a default converted RAW file (although obviously you shoot RAW for reasons of flexibility). Surprisingly the Normal compression mode which effectively halves the size of the output file also appears clean with no obvious artifacts at 100% view. At the smaller image sizes the EOS 350D's downsampling interpolation is very good, nice clean aliasing with no noticeable 'jaggies'.
Image parameter Presets
Just like the EOS 300D and 20D the 350D now has two preset and three user definable parameter sets. Parameter 1 preset has a contrast, sharpness and saturation setting of +1, Parameter 2 preset is neutral (0 for all settings). Hence by default you get an image with more punch but if you post-process more often then Parameter 2 may be the better choice.
Scene parameter preset samples
|Parameter 1||Parameter 2|
In another improvement over the EOS 300D the selection of color space has now been separated from image parameter. This means that you can independently select the sRGB or Adobe RGB color spaces and also have image processing adjustments applied. Note that images taken in the Adobe RGB color space have their filename prefixed with an underscore (_) this complies with DCF 2.0 (Exif 2.21)*. Place your mouse over the label below the image to see the GretagMacbeth ColorChecker chart taken in each color space.
|sRGB||Adobe RGB (converted to sRGB)|
* This has nothing in particular to do with Canon but this renaming system makes it difficult to keep your images in the correct order if you don't routinely rename them by date/time.
Color space: CIE u'v' Color Distribution chart
Note that in these samples the Adobe RGB image has not been converted to sRGB and so to view it correctly you will have to load it into a color space aware photo application and assign the Adobe RGB color space. Below each sample is the CIE u'v' Color Distribution chart; larger gray triangle approximately represents the range of color which the human eye can resolve, the inner triangle the available gamut in each color space (sRGB or Adobe RGB).
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