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Output image file quality / JPEG artifacts


Standard Test Scene
The EOS 20D provides seven different image size / quality combinations. You can choose from image sizes of 3504 x 2336 (Large), 2544 x 1696 (Medium) or 1728 x 1152 (Small) in combination with either Fine JPEG or Normal JPEG quality settings. In addition of course the EOS 20D also provides a RAW capture mode which in effect dumps the RAW data direct from the CMOS sensor into a losslessly compressed file (around 9.0 MB per image). Note that RAW files are in the new .CR2 file format.

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 EOS Viewer Utility 1.1.

3504 x 2336 RAW (Uncompressed)
8,861 KB .CR2 (not for download)
3504 x 2336 (L) JPEG Fine
3,496 KB .JPG
3504 x 2336 (L) JPEG Normal
1,758 KB .JPG
2544 x 1696 (M) JPEG Fine
2,027 KB .JPG
 

1728 x 1152 (S) JPEG Fine
1,115 KB .JPG

 

The EOS 20D's 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 20D's downsampling interpolation is very good, nice clean aliasing with no noticeable 'jaggies'.

Image parameter Presets

The EOS 20D 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). This means that (a) by default you get a punchier image out of the EOS 20D compared to the EOS 10D and that (b) if you wish to compare the two cameras you need to set the EOS 20D to Parameter 2 (neutral).

Scene parameter preset samples

Parameter 1 Parameter 2

GretagMacBeth ColorChecker parameter preset samples

Below is GretagMacbeth ColorChecker shot in the two preset modes as well as EOS 10D equivalent shots. The first thing that we notice is that the EOS 20D's images (despite being the same exposure as the EOS 10D) are lighter, this is true across the tonal range (hence this isn't a contrast difference). Secondly color response and saturation is very similar. Place your mouse over the label below the chart to see that image.

EOS 20D Parameter 1
+1, +1, +1, 0
EOS 20D Parameter 2
0, 0, 0, 0
EOS 10D Set 1*
+1, +1, +1, 0
EOS 10D Standard
0, 0, 0, 0

* A custom user set was created with a contrast, sharpness and saturation setting of +1

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