Output image file quality / JPEG artifacts

Standard Test Scene

The 8400 provides no less than seven different output image size options, JPEG (at four compression levels), TIFF and RAW mode (which is essentially a record of data straight from the CCD without processing, the 'digital negative'). New to the 8400 and 8800 is the 'Extra' JPEG mode which uses a very low compression to achieve an image which really is as-good-as-a-TIFF.

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 by Adobe Photoshop CS Camera RAW 2.4 (the supplied PictureProject software crashed when trying to convert the RAW file).

3264 x 2448 RAW (Adobe Photoshop CS)
12,375 KB .NEF (not for download)
3264 x 2448 (8M) JPEG Extra
5,590 KB .JPG (7 bits per pixel)
3264 x 2448 (8M) JPEG Fine
2,293 KB .JPG (3 bits per pixel)
3264 x 2448 (8M) JPEG Normal
1,567 KB .JPG (2 bits per pixel)
3264 x 2448 (8M) JPEG Basic
953 KB .JPG (1 bit per pixel)
2048 x 1536 (3M) JPEG Fine
1,010 KB .JPG (3 bits per pixel)

1280 x 960 (1M) JPEG Fine
426 KB .JPG (3 bits per pixel)


The new JPEG Extra mode delivers extremely high quality which would be virtually impossible to distinguish from an identical TIFF image. Having said that it's very difficult to see any JPEG artifacts even at the Fine compression level, I'm sure this is the setting most people will use most of the time. Dropping down to Normal you can find some artifacts (if you look hard) and obviously in Basic mode the artifacts are clearly visible.