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Output image file quality / JPEG artifacts


Standard Test Scene
The EOS 350D 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 350D 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 .CR2 file format.

You can also shoot RAW + JPEG which captures one RAW and one JPEG file separately.

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
981 KB .JPG

 

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

Color space

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).

sRGB Adobe RGB
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Comments

Total comments: 4
reanim888

As I know the XT can simultaneously record raw and high-quality JPEG files, whereas the original Rebel's raw-plus-JPEG mode could capture only lower-quality JPEGs. You can also override the automatic seven-point AiAF focusing--a good thing, given its occasional unreliability--but doing so requires first pushing a button to initialize the process, then navigating to one of the seven points using either the directional buttons or the main dial. It's a little clunky, but you can actually streamline the process by changing the camera's custom settings to eliminate the first step.
What do you think about it?

1 upvote
Sam Spark

Canon EOS Rebel line of DSLR cameras are the best for those wanting to get into more advanced photography. The main reason for this is that they allow full manual controls and the interchangeable lenses. These allow you to change so much of how the cameras functions in different lighting situations.The EOS Rebel T5 is a fast camera, has a huge bright 3.0-inch LCD monitor and exceptional autofocus with a 9-point AF system.One can take beautiful pictures automatically.

1 upvote
Pascal Parvex

Bought this version (Rebel XT) for about $350 two years ago, refurbished. Still works well and has a good image quality.

1 upvote
DaytonR

Thats amazing, I also saw one mint condition one in a computer shop and another in a camera store , its gorgeous camera to carry around ! :)

0 upvotes
Total comments: 4