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JPEG/RAW Image Size & Quality

The E-20 allows you to reprogram the three JPEG presets 'SHQ, HQ and SQ' to your own combination of resolution (2560 x 1920, 1792 x 1344, 1280 x 960, 1024 x 768 or 640 x 480) and JPEG compression ratio (1/2.7, 1/4, 1/8). On top of this you can also use uncompressed TIFF (15,616 KB each) or Olympus RAW (.ORF: 9,676 KB). The pre-production camera used for this review was not supplied with the Olympus RAW conversion software, as soon as we receive a full production camera I'll add a RAW sample below.


Standard Test Scene

To give an impression of what some of the combinations of image size and quality produce the table below is a cross reference of some of them:

  • 2560 x 1920 TIFF
  • 2560 x 1920 JPEG 1/2.7
  • 2560 x 1920 JPEG 1/4
  • 2560 x 1920 JPEG 1/8
  • 1792 x 1344 JPEG 1/4
  • 1280 x 960 JPEG 1/4

Images below are cropped 240 x 100 area of the image magnified 200% (nearest neighbour).


 
2560 x 1920
RAW
ORF 9,697 KB - not available for download
TIFF
TIFF 15,616 KB - not available for download
JPEG
1/2.7

3,662 KB (warning: very large file)
JPEG
1/4

2,581 KB (warning: very large file)
JPEG
1/8

1,268 KB
 

 
1792 x 1344
JPEG
1/4

1,147 KB
 

 
1280 x 960

JPEG
1/4


586 KB

With the superbly high quality 1/2.7 JPEG option you'd be hard pressed to find a use for the TIFF option (especially considering how long it takes to save an image this large). The 1/4 JPEG option is virtually indistinguishable from 1/2.7, 1/8 increases artifacts slightly but still offers an excellent combination of image quality and storage size / speed.


Image Processing Adjustments

The E-20 provides control over image contrast and sharpening. You can select one level above or below the standard contrast or sharpening settings, Olympus's recent consumer digital cameras offer a total of five levels of adjustment. What's also surprising is that there's no control over colour saturation.

Contrast

Contrast: High Contrast: Normal Contrast: Low

The contrast setting of 'low' provides a very flat looking image which preserves optimum shadow and highlight detail (and thus dynamic range). Clearly this kind of image would require a little adjustment afterwards but it would be useful for those photographers who do so as a matter of course.

Sharpening

Sharpening: Hard Sharpening: Normal Sharpening: Soft

As you can see the difference between the E-20's sharpening levels is very subtle. Those users who are looking for the cleanest most 'artifact free' image who will either be reducing in size or sharpening later should stick to Soft sharpening setting.


Progressive Scan mode

The E-20 uses an interlaced scan CCD (much like many other digital cameras). This means that data is read from the CCD in two 'fields', first the even rows and then the odd rows. The E-20's progressive scan mode appears to simply skip the transfer of one of the fields (even or odd, it's difficult to tell), this yields the same horizontal resolution but far less vertical resolution (to me it looks like much less than half, see the samples below).

The only advantage of the progressive scan mode is that in this mode the CCD appears to be able to activate itself as an electronic shutter and achieve shutter speeds above the 1/640 sec limit produced by the single iris aperture / shutter mechanism.

Progressive Scan
Interlaced Scan
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