Output image file quality / JPEG artifacts

Standard Test Scene

The Kodak DCS Pro SLR/c provides two different image output options, RAW and JPEG (both Standard and JPEG-ERI). In JPEG mode you can select between 13.5, 6.0, 3.4 and 0.8 megapixel sizes in combination with three compression levels. In RAW mode you can select between 13.5, 6.0 and 3.4 megapixel sizes. Kodak RAW images have a '.DCR' file extension and are losslessly compressed (similar to Zip compression). A full resolution RAW image from the SLR/c weighs in at around 13 MB.

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 Kodak DCS Photo Desk 4.0.1.2.

Settings: ISO 160, Canon EF 24-70 mm F2.8L, Normal NR, Low Sharpening, Product Look

4500 x 3000 RAW 14,140 KB .DCR (not for download)	4500 x 3000 JPEG (Quality III) 3,526 KB .JPG
4500 x 3000 JPEG (Quality II) 2,984 KB .JPG	4500 x 3000 JPEG (Quality I) 2,523 KB .JPG
3000 x 2000 JPEG (Quality III) 2,075 KB .JPG	2250 x 1500 JPEG (Quality III) 1,233 KB .JPG
1125 x 750 JPEG (Quality III) 576 KB .JPG

At both JPEG quality levels III and II it's very difficult to see any JPEG artifacts or loss of image quality, drop down to level I and it is possible to see some 'mosquito' type artifacts around areas of image detail. The SLR/c's downsampling interpolation algorithm seems fairly good with a very crisp response and no noticeable 'jaggies'.

Look profiles

A 'Look profile' is a combination of tone curve and color response designed to achieve a particular output appearance. The SLR/c comes with four built-in Look profiles for in-camera JPEG, these are:

• Product - More contrast and higher levels of color saturation
• Portrait - Lower contrast with more detail in highlights and shadows
• Wedding - Product with neutral shadows
• Event - High saturation with optimized skin tones

In addition you can also purchase packs of Look profiles for the processing of RAW images, it is not possible to add or modify the Look profiles built into the camera (which is a pity). Below are samples of the same scene shot in the four different built-in Look profiles.

Settings: ISO 160, Canon EF 24-70 mm F2.8L, Normal NR, Low Sharpening

Look		Luminosity histogram
P r o d u c t
P o r t r a i t
W e d d i n g
E v e n t