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Output image file quality / JPEG artifacts


Standard Test Scene
The E-500 has three JPEG presets; SHQ, HQ and SQ. SHQ and HQ are both at full resolution (3264 x 2448), however the HQ setting can be set to either 1/4, 1/8 or 1/12 JPEG compression. The SQ setting can be any one of six image sizes in combination with either 1/2.7, 1/4, 1/8 or 1/12 JPEG compression. In addition the E-500 also provides uncompressed TIFF, RAW (Olympus .ORF) and RAW + JPEG (any of SHQ, HQ or SQ).

Below you will find 200% magnified crops of the same 240 x 100 portion of the center of a sequence of images taken at full size but different output settings. The RAW file was converted to a TIFF using Olympus Master 1.3.

3264 x 2448 TIFF (Uncompressed) - 23,902 KB .TIF (not for download) (VGA TIFF crop)
3264 x 2448 RAW (Uncompressed) - 13,797 KB .ORF (not for download) (VGA TIFF crop)
3264 x 2448 JPEG SHQ (1/2.7) - 5,289 KB .JPG
3264 x 2448 JPEG HQ (1/4) - 4,181 KB .JPG
3264 x 2448 JPEG HQ (1/8) - 1,807 KB .JPG

As we've seen on previous Olympus cameras the SHQ JPEG is as good as lossless and makes the TIFF option pretty redundant (you'll be hard pushed to see a difference). The optimum mode is probably HQ at the 1/4 setting which delivers files of around 4 MB with virtually not artifacts at all. Higher compression than this (1/8 or 1/12 settings) do lead to some JPEG artifacts, especially around detail edges.

Color space

The E-500 provides the independent selection of output color space, you can select from sRGB or Adobe RGB. Via the menus this is buried on the second setup menu, with the control panel display enabled you can press OK and access it as a shortcut.

Images taken in the Adobe RGB color space have their filename prefixed with an underscore (_) this complies with DCF 2.0 (Exif 2.21)*. It looks as though Olympus has fixed the color space issue we discovered in our E-300 review, color response is virtually identical between the two modes (apart from Adobe RGB offering a wider gamut). Place your mouse over the label to see a ColorChecker chart shot in the respective mode.

sRGB Adobe RGB (converted to sRGB)

* This has nothing in particular to do with Olympus 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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